Systems, methods, and interfaces for use in cardiac evaluation

ABSTRACT

Systems, interfaces, and methods are described herein for evaluation and adjustment cardiac therapy. The systems, interfaces, and methods may utilize, or include, a graphical user interface to display various information with respect to a plurality of external electrodes and electrical activity monitored using such external electrodes and to allow a user to adjust what information to display.

The disclosure herein relates to systems, methods, and interfaces foruse in cardiac evaluation using external electrode apparatus.

Implantable medical devices (IMDs), such as implantable pacemakers,cardioverters, defibrillators, or pacemaker-cardioverter-defibrillators,provide therapeutic electrical stimulation to the heart. IMDs mayprovide pacing to address bradycardia, or pacing or shocks in order toterminate tachyarrhythmia, such as tachycardia or fibrillation. In somecases, the medical device may sense intrinsic depolarizations of theheart, detect arrhythmia based on the intrinsic depolarizations (orabsence thereof), and control delivery of electrical stimulation to theheart if arrhythmia is detected based on the intrinsic depolarizations.

IMDs may also provide cardiac resynchronization therapy (CRT), which isa form of pacing. CRT involves the delivery of pacing to the leftventricle, or both the left and right ventricles. The timing andlocation of the delivery of pacing pulses to the ventricle(s) may beselected to improve the coordination and efficiency of ventricularcontraction.

Systems for implanting medical devices may include workstations or otherequipment in addition to the implantable medical device itself. In somecases, these other pieces of equipment assist the physician or othertechnician with placing the intracardiac leads at particular locationson or in the heart. In some cases, the equipment provides information tothe physician about the electrical activity of the heart and thelocation of the intracardiac lead.

SUMMARY

The exemplary systems, methods, and interfaces described herein may beconfigured to assist a user (e.g., a physician) in evaluating a patientand evaluating cardiac therapy (e.g., cardiac therapy being performed ona patient during and/or after implantation of cardiac therapyapparatus). In one or more embodiments, the systems, methods, andinterfaces may be described as being noninvasive. For example, in someembodiments, the systems, methods, and interfaces may not need, orinclude, implantable devices such as leads, probes, sensors, catheters,implantable electrodes, etc. to monitor, or acquire, a plurality ofcardiac signals from tissue of the patient for use in evaluating thepatient and/or cardiac therapy being delivered to the patient. Instead,the systems, methods, and interfaces may use electrical measurementstaken noninvasively using, e.g., a plurality of external electrodesattached to the skin of a patient about the patient's torso.

It may be described that the illustrative systems, methods, andinterfaces may be able to, or are configured to, display a live, orinteractive, feedback on electrode connectivity with a three-statestatus. The three-state statuses may include not in contact, poorsignal, or good signal. In at least one embodiment, one or moreprocesses, or algorithms, may involve monitoring signal characteristicsof each of the electrodes to determine the three-status state of theelectrode. An illustrative graphical user interface may depict, ordisplay, a graphical map of a plurality of electrode graphical elements,each corresponding to a physical, external electrode attached, orcoupled, to the patient. An effectiveness value such as a three-statestatus value or indicator may be displayed proximate (e.g., within, nextto, as part of, etc.) each of the electrode graphical elements suchthat, e.g., a user may quickly ascertain the effectiveness or status ofeach external electrode by viewing, or glancing upon, the illustrativegraphical user interface.

Further, the illustrative systems, methods, and interfaces may includeor may utilize one or more sorting processes, or algorithms, based ontwo or more metrics of electrical heterogeneity, or dyssynchrony, basedon a plurality of external electrodes attached or coupled to the torsoof a patient. For example, the processes may sort, or rank, cardiacresynchronization therapy settings based on improvements in the standarddeviation of activation times (SDAT) and/or a statistic (e.g., average,media, etc.) of left ventricular activation times (LVAT) measured usingthe plurality of external electrodes. In at least one embodiment, SDATmay be used as the primary variable for sorting but, in case of two ormore settings within a selected range (e.g., such as 3%) of SDATimprovement, LVAT may be further used to sort the two or more settings(e.g. to break the tie).

Still further, the illustrative systems, methods, and interfaces mayinclude displaying electrode numbers on graphical maps of activationtimes and further indicating the electrodes where map data may have beeninterpolated due to missing signals. In one or more embodiments,activation times between two neighboring electrodes may be different dueto lines of block, and an indication may be displayed on the graphicalmaps indicating the location of the block within the map. For example,adjacently-measured activation times may indicate a block if theactivation times are different by a selected period of time (e.g., morethan 50 milliseconds (ms)) (further, e.g., such adjacently-measuredactivation times may not be interpolated). The graphical map includinglines of block may be used for implant guidance on where to place alead.

The illustrative graphical user interfaces may be described as include avariety of different types of data displayed in a plurality of differentways. Some of the types of data may be indicative of the system statusof the illustrative systems and methods described herein. For example,the illustrative graphical user interfaces may, or may be configured to,provide interactive feedback on status of electrode connection based onquality check of electrode signals, display the electrode layout on atorso model using different sizes of torso models fitting with differentsized electrode apparatus (e.g., different sizes electrode belts or vestbased on inputs of weight, height, gender, age, etc. to automaticallyselect/recommend the appropriate size), adjust the location of theexternal electrodes on the model to match locations as applied to thetorso, e.g., based on user input of patient measurements such as, e.g.,chest circumference measurements, and determine which externalelectrodes are not in good contact, based on low amplitude or baselinewander (e.g., processes, or algorithms, may be utilized to find thebaseline used for the analysis).

The illustrative graphical user interfaces may, or may be configured to,display color-coded activation maps (e.g., two-dimensional maps, torsomodel maps, etc.) with external electrodes with invalid signals marked,which include areas on the map that are interpolated due to missingelectrodes/invalid signals. The illustrative graphical user interfacesmay, or may be configured to, to provide interpolation of electricalactivation time data that is missing in areas based on activation timesfrom neighboring electrodes or nearest neighbors with validsignals/activation times. Further, various criteria for invalidelectrodes may be used to determine missing electrodes or electrodeswith invalid signals. Electrode (ECG) signals from at least one ormultitude of channels may be selectable either automatically or throughuser interaction. Further, the beat on which the data was processed anddisplayed may be indicated on the graphical user interface, and a usermay have the ability to override automatic selection and pick adifferent beat.

The illustrative graphical user interfaces may, or may be configured to,include two planar views of the activation maps such as an anteriorplanar view and a posterior planar view. Further, three-dimensional (3D)views may also be provided or displayed such as a left-lateral 3D viewand a right-lateral 3D view. Further, such 3D view may be rotatableeither automatically or through user interaction with the interface.

The illustrative graphical user interfaces may, or may be configured to,include a summary screen that displays, or depict, activation maps ofmultiple different cardiac therapy settings with one or more options torank selected cardiac therapy settings in order of improvement ofelectrical synchrony. Further, the summary screen could also include anactivation map along with a physical map of lead pacing location. A usercould select or input where the lead was placed or the electrode ispacing from (e.g., apical/mid-basal location in a posterior/posteriorlateral/coronary sinus vein). The electrode apparatus and associatedequipment may be wireless (e.g., Bluetooth communication) or wiredcommunication with an implantable device, a programmer, and a tabletcomputer.

The illustrative systems, methods, and interfaces may further include anautomated routine using a baseline (e.g., intrinsic or right ventricularpacing) rhythm of the patient and a left ventricle-only pacing and/orbiventricular pacing at various atrioventricular and interventriculardelays for different pacing vectors and sort settings (which, forexample, may include a combination of timing and pacing vector).Processing and sensing circuitry including an amplifier may be describedas collecting cardiac cycles simultaneously from the external electrodesand sending a chosen cardiac cycle for each setting to an implantabledevice or programmer for processing of activation times anddetermination of cardiac electrical dyssynchrony. In one example, thedevice may overdrive pace by a predetermined rate above the baselinerhythm for this evaluation.

The illustrative systems, methods, and interfaces may, or be configuredto, sort selected settings according to improvements in metrics ofelectrical dyssynchrony such as, e.g., a standard deviation ofactivation times from all electrodes (SDAT) and average left ventricularactivation time (LVAT). Further, certain settings may be automaticallyexcluded in response to determination of high pacing thresholds and/orphrenic nerve stimulation.

In one or more embodiments, the cardiac therapy settings having, orwith, a maximum reduction in SDAT and filters settings with SDATreduction within 3% percentage points of the maximum reduction may beselected. Then, a maximum improvement in LVAT from the selected, orfiltered, settings may be determined and the difference between LVATimprovements for each of the selected settings may be evaluated. Anysetting that has an LVAT improvement that is less than about by 30%points or more (or another designated amount) may be excluded/demoted.All the remaining settings may then be considered as options for finalprogramming of the cardiac therapy. Additionally, the sort settings maybe further configured to optimize both device longevity and improvementfrom baseline, e.g., if two pacing sites are similarly beneficialhemodynamically, the pacing site with better device longevity may beselected. Conversely, if two pacing sites have similar device longevity,the one with better hemodynamics may be chosen.

It may be further described that the illustrative systems, methods, andinterfaces may provide user with the means to record and save a fivesecond ECG, SDAT, LVAT, and activation maps for intrinsic or RV pacedrhythms. Further, the illustrative systems, methods, and interfaces mayprovide users with the means to record and save a 5 second ECG, % 4 inSDAT and LVAT from intrinsic or RV paced, and activation maps forvarious combinations of CRT settings (paced scenarios). Still further,the illustrative systems, methods, and interfaces may allow users tosort paced scenarios by % 4 in SDAT and LVAT from Intrinsic for eachpaced scenario, and may provide users with information to program thebest CRT settings.

The above summary is not intended to describe each embodiment or everyimplementation of the present disclosure. A more complete understandingwill become apparent and appreciated by referring to the followingdetailed description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary system including electrodeapparatus, display apparatus, and computing apparatus.

FIGS. 2-3 are diagrams of exemplary external electrode apparatus formeasuring torso-surface potentials.

FIG. 4 is an illustrative graphical user interface depicting electrodestatus information, e.g., for use with the systems and externalelectrode apparatus of FIGS. 1-3.

FIGS. 5A-5B are illustrative graphical user interfaces depicting, amongother things, a graphical map of electrical activation, e.g., for usewith the systems and external electrode apparatus of FIGS. 1-3.

FIG. 5C is the graphical user interface of FIG. 5B including an enlargedgraphical region depicting a single cardiac cycle.

FIG. 6 is an illustrative graphical user interface depicting, amongother things, a graphical map of electrical activation and cardiactherapy scenario graphical, e.g., for use with the systems and externalelectrode apparatus of FIGS. 1-3.

FIG. 7 is an illustrative graphical user interface depicting, amongother things, a plurality of graphical maps of electrical activationcorresponding to different cardiac therapy scenarios, e.g., for use withthe systems and external electrode apparatus of FIGS. 1-3.

FIG. 8A is an illustrative graphical user interface for evaluation andsorting of cardiac therapy scenarios including a cardiac therapyscenario selection region, e.g., for use with the systems and externalelectrode apparatus of FIGS. 1-3.

FIG. 8B is an illustrative graphical user interface depicting a rankingof selected cardiac therapy scenarios from the cardiac therapy scenarioselection region of FIG. 8A, e.g., for use with the systems and externalelectrode apparatus of FIGS. 1-3.

FIG. 8C is another illustrative graphical user interface depicting morerankings of selected cardiac therapy scenarios, e.g., for use with thesystems and external electrode apparatus of FIGS. 1-3.

FIG. 9 is a diagram of an exemplary system including an exemplaryimplantable medical device (IMD).

FIG. 10A is a diagram of the exemplary IMD of FIG. 9.

FIG. 10B is a diagram of an enlarged view of a distal end of theelectrical lead disposed in the left ventricle of FIG. 10A.

FIG. 11A is a block diagram of an exemplary IMD, e.g., of the systems ofFIGS. 9-10.

FIG. 11B is another block diagram of an exemplary IMD (e.g., animplantable pulse generator) circuitry and associated leads employed inthe systems of FIGS. 9-10.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following detailed description of illustrative embodiments,reference is made to the accompanying figures of the drawing which forma part hereof, and in which are shown, by way of illustration, specificembodiments which may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from (e.g., still falling within) the scope of the disclosurepresented hereby.

Exemplary systems, methods, and interfaces shall be described withreference to FIGS. 1-11. It will be apparent to one skilled in the artthat elements or processes from one embodiment may be used incombination with elements or processes of the other embodiments, andthat the possible embodiments of such systems, methods, and interfacesusing combinations of features set forth herein is not limited to thespecific embodiments shown in the Figures and/or described herein.Further, it will be recognized that the embodiments described herein mayinclude many elements that are not necessarily shown to scale. Stillfurther, it will be recognized that timing of the processes and the sizeand shape of various elements herein may be modified but still fallwithin the scope of the present disclosure, although certain timings,one or more shapes and/or sizes, or types of elements, may beadvantageous over others.

A plurality of electrocardiogram (ECG) signals (e.g., torso-surfacepotentials) may be measured, or monitored, using a plurality of externalelectrodes positioned about the surface, or skin, of a patient. The ECGsignals may be used to evaluate and configure cardiac therapy such as,e.g., cardiac therapy provide by an implantable medical deviceperforming cardiac resynchronization therapy (CRT). As described herein,the ECG signals may be gathered or obtained noninvasively since, e.g.,implantable electrodes may not be used to measure the ECG signals.Further, the ECG signals may be used to determine cardiac electricalactivation times, which may be used to generate various metrics (e.g.,electrical heterogeneity information) that may be used by a user (e.g.,physician) to optimize one or more settings, or parameters, of cardiactherapy (e.g., pacing therapy) such as CRT.

Various exemplary systems, methods, and graphical user interfaces may beconfigured to use electrode apparatus including external electrodes,display apparatus, and computing apparatus to noninvasively assist auser (e.g., a physician) in the evaluation of cardiac health and/or theconfiguration (e.g., optimization) of cardiac therapy. An exemplarysystem 100 including electrode apparatus 110, computing apparatus 140,and a remote computing device 160 is depicted in FIG. 1.

The electrode apparatus 110 as shown includes a plurality of electrodesincorporated, or included, within a band wrapped around the chest, ortorso, of a patient 14. The electrode apparatus 110 is operativelycoupled to the computing apparatus 140 (e.g., through one or wiredelectrical connections, wirelessly, etc.) to provide electrical signalsfrom each of the electrodes to the computing apparatus 140 for analysis,evaluation, etc. Exemplary electrode apparatus may be described in U.S.Pat. No. 9,320,446 entitled “Bioelectric Sensor Device and Methods”filed Mar. 27, 2014 and issued on Mar. 26, 2016, which is incorporatedherein by reference in its entirety. Further, exemplary electrodeapparatus 110 will be described in more detail in reference to FIGS.2-3.

Although not described herein, the exemplary system 100 may furtherinclude imaging apparatus. The imaging apparatus may be any type ofimaging apparatus configured to image, or provide images of, at least aportion of the patient in a noninvasive manner. For example, the imagingapparatus may not use any components or parts that may be located withinthe patient to provide images of the patient except noninvasive toolssuch as contrast solution. It is to be understood that the exemplarysystems, methods, and interfaces described herein may further useimaging apparatus to provide noninvasive assistance to a user (e.g., aphysician) to locate, or place, one or more pacing electrodes proximatethe patient's heart in conjunction with the configuration of cardiactherapy.

For example, the exemplary systems and methods may provide image guidednavigation that may be used to navigate leads including electrodes,leadless electrodes, wireless electrodes, catheters, etc., within thepatient's body while also providing noninvasive cardiac therapyconfiguration including determining an effective, or optimal, LVADparameters A-V interval, etc. Exemplary systems and methods that useimaging apparatus and/or electrode apparatus may be described in U.S.Pat. App. Pub. No. 2014/0371832 to Ghosh published on Dec. 18, 2014,U.S. Pat. App. Pub. No. 2014/0371833 to Ghosh et al. published on Dec.18, 2014, U.S. Pat. App. Pub. No. 2014/0323892 to Ghosh et al. publishedon Oct. 30, 2014, U.S. Pat. App. Pub. No. 2014/0323882 to Ghosh et al.published on Oct. 20, 2014, each of which is incorporated herein byreference in its entirety.

Exemplary imaging apparatus may be configured to capture x-ray imagesand/or any other alternative imaging modality. For example, the imagingapparatus may be configured to capture images, or image data, usingisocentric fluoroscopy, bi-plane fluoroscopy, ultrasound, computedtomography (CT), multi-slice computed tomography (MSCT), magneticresonance imaging (MM), high frequency ultrasound (HIFU), opticalcoherence tomography (OCT), intra-vascular ultrasound (IVUS), twodimensional (2D) ultrasound, three dimensional (3D) ultrasound, fourdimensional (4D) ultrasound, intraoperative CT, intraoperative Mill,etc. Further, it is to be understood that the imaging apparatus may beconfigured to capture a plurality of consecutive images (e.g.,continuously) to provide video frame data. In other words, a pluralityof images taken over time using the imaging apparatus may provide videoframe, or motion picture, data. Additionally, the images may also beobtained and displayed in two, three, or four dimensions. In moreadvanced forms, four-dimensional surface rendering of the heart or otherregions of the body may also be achieved by incorporating heart data orother soft tissue data from a map or from pre-operative image datacaptured by MM, CT, or echocardiography modalities. Image datasets fromhybrid modalities, such as positron emission tomography (PET) combinedwith CT, or single photon emission computer tomography (SPECT) combinedwith CT, could also provide functional image data superimposed ontoanatomical data, e.g., to be used to navigate implantable apparatus totarget locations within the heart or other areas of interest.

Systems and/or imaging apparatus that may be used in conjunction withthe exemplary systems and method described herein are described in U.S.Pat. App. Pub. No. 2005/0008210 to Evron et al. published on Jan. 13,2005, U.S. Pat. App. Pub. No. 2006/0074285 to Zarkh et al. published onApr. 6, 2006, U.S. Pat. No. 8,731,642 to Zarkh et al. issued on May 20,2014, U.S. Pat. No. 8,861,830 to Brada et al. issued on Oct. 14, 2014,U.S. Pat. No. 6,980,675 to Evron et al. issued on Dec. 27, 2005, U.S.Pat. No. 7,286,866 to Okerlund et al. issued on Oct. 23, 2007, U.S. Pat.No. 7,308,297 to Reddy et al. issued on Dec. 11, 2011, U.S. Pat. No.7,308,299 to Burrell et al. issued on Dec. 11, 2011, U.S. Pat. No.7,321,677 to Evron et al. issued on Jan. 22, 2008, U.S. Pat. No.7,346,381 to Okerlund et al. issued on Mar. 18, 2008, U.S. Pat. No.7,454,248 to Burrell et al. issued on Nov. 18, 2008, U.S. Pat. No.7,499,743 to Vass et al. issued on Mar. 3, 2009, U.S. Pat. No. 7,565,190to Okerlund et al. issued on Jul. 21, 2009, U.S. Pat. No. 7,587,074 toZarkh et al. issued on Sep. 8, 2009, U.S. Pat. No. 7,599,730 to Hunteret al. issued on Oct. 6, 2009, U.S. Pat. No. 7,613,500 to Vass et al.issued on Nov. 3, 2009, U.S. Pat. No. 7,742,629 to Zarkh et al. issuedon Jun. 22, 2010, U.S. Pat. No. 7,747,047 to Okerlund et al. issued onJun. 29, 2010, U.S. Pat. No. 7,778,685 to Evron et al. issued on Aug.17, 2010, U.S. Pat. No. 7,778,686 to Vass et al. issued on Aug. 17,2010, U.S. Pat. No. 7,813,785 to Okerlund et al. issued on Oct. 12,2010, U.S. Pat. No. 7,996,063 to Vass et al. issued on Aug. 9, 2011,U.S. Pat. No. 8,060,185 to Hunter et al. issued on Nov. 15, 2011, andU.S. Pat. No. 8,401,616 to Verard et al. issued on Mar. 19, 2013, eachof which is incorporated herein by reference in its entirety.

The computing apparatus 140 and the remote computing device 160 may eachinclude display apparatus 130, 160, respectively, that may be configuredto display and analyze data such as, e.g., electrical signals (e.g.,electrocardiogram data), electrical activation times, electricalheterogeneity information, etc. For example, one cardiac cycle, or oneheartbeat, of a plurality of cardiac cycles, or heartbeats, representedby the electrical signals collected or monitored by the electrodeapparatus 110 may be analyzed and evaluated for one or more metricsincluding activation times and electrical heterogeneity information thatmay be pertinent to the therapeutic nature of one or more parametersrelated to cardiac therapy such as, e.g., pacing parameters, leadlocation, etc. More specifically, for example, the QRS complex of asingle cardiac cycle may be evaluated for one or more metrics such as,e.g., QRS onset, QRS offset, QRS peak, electrical heterogeneityinformation, electrical activation times, left ventricular or thoracicstandard deviation of electrical activation times (LVED), standarddeviation of activation-times (SDAT), average left ventricular orthoracic surrogate electrical activation times (LVAT), referenced toearliest activation time, QRS duration (e.g., interval between QRS onsetto QRS offset), difference between average left surrogate and averageright surrogate activation times, relative or absolute QRS morphology,difference between a higher percentile and a lower percentile ofactivation times (higher percentile may be 90%, 80%, 75%, 70%, etc. andlower percentile may be 10%, 15%, 20%, 25% and 30%, etc.), otherstatistical measures of central tendency (e.g., median or mode),dispersion (e.g., mean deviation, standard deviation, variance,interquartile deviations, range), etc. Further, each of the one or moremetrics may be location specific. For example, some metrics may becomputed from signals recorded, or monitored, from electrodes positionedabout a selected area of the patient such as, e.g., the left side of thepatient, the right side of the patient, etc.

In at least one embodiment, one or both of the computing apparatus 140and the remote computing device 160 may be a server, a personalcomputer, or a tablet computer. The computing apparatus 140 may beconfigured to receive input from input apparatus 142 (e.g., a keyboard)and transmit output to the display apparatus 130, and the remotecomputing device 160 may be configured to receive input from inputapparatus 162 (e.g., a touchscreen) and transmit output to the displayapparatus 170. One or both of the computing apparatus 140 and the remotecomputing device 160 may include data storage that may allow for accessto processing programs or routines and/or one or more other types ofdata, e.g., for analyzing a plurality of electrical signals captured bythe electrode apparatus 110, for determining QRS onsets, QRS offsets,medians, modes, averages, peaks or maximum values, valleys or minimumvalues, for determining electrical activation times, for driving agraphical user interface configured to noninvasively assist a user inconfiguring one or more pacing parameters, or settings, such as, e.g.,pacing rate, ventricular pacing rate, A-V interval, V-V interval, pacingpulse width, pacing vector, multipoint pacing vector (e.g., leftventricular vector quad lead), pacing voltage, pacing configuration(e.g., biventricular pacing, right ventricle only pacing, left ventricleonly pacing, etc.), and arrhythmia detection and treatment, rateadaptive settings and performance, etc. Further, in at least oneembodiment, one or both of the computing apparatus 140 and the remotecomputing device 160 may include data storage that may allow for accessto processing programs or routines and/or one or more other types ofdata, e.g., for driving a graphical user interface configured tononinvasively assist a user in configuring one or more cardiac therapyparameters, or settings, such LVAD pump speed, LVAD pump throughput,LVAD pump power, LVAD pump current, pump inflow gimbal angle, automaticalgorithmic responses to events such as pump suction, patient activitylevel changes, and physiologic parameter inputs, enabling/disablingperiodic pump speed modulation features such as the Lavare cycle.

The computing apparatus 140 may be operatively coupled to the inputapparatus 142 and the display apparatus 130 to, e.g., transmit data toand from each of the input apparatus 142 and the display apparatus 130,and the remote computing device 160 may be operatively coupled to theinput apparatus 162 and the display apparatus 170 to, e.g., transmitdata to and from each of the input apparatus 162 and the displayapparatus 170. For example, the computing apparatus 140 and the remotecomputing device 160 may be electrically coupled to the input apparatus142, 162 and the display apparatus 130, 170 using, e.g., analogelectrical connections, digital electrical connections, wirelessconnections, bus-based connections, network-based connections,internet-based connections, etc. As described further herein, a user mayprovide input to the input apparatus 142, 162 to view and/or select oneor more pieces of configuration information related to the cardiactherapy delivered by cardiac therapy apparatus such as, e.g., animplantable medical device.

Although as depicted the input apparatus 142 is a keyboard and the inputapparatus 162 is a touchscreen, it is to be understood that the inputapparatus 142, 162 may include any apparatus capable of providing inputto the computing apparatus 140 and the computing device 160 to performthe functionality, methods, and/or logic described herein. For example,the input apparatus 142, 162 may include a keyboard, a mouse, atrackball, a touchscreen (e.g., capacitive touchscreen, a resistivetouchscreen, a multi-touch touchscreen, etc.), etc. Likewise, thedisplay apparatus 130, 170 may include any apparatus capable ofdisplaying information to a user, such as a graphical user interface132, 172 including electrode status information, graphical maps ofelectrical activation, a plurality of signals for the externalelectrodes over one or more heartbeats, QRS complexes, various cardiactherapy scenario selection regions, various rankings of cardiac therapyscenarios, various pacing parameters, electrical heterogeneityinformation, textual instructions, graphical depictions of anatomy of ahuman heart, images or graphical depictions of the patient's heart,graphical depictions of locations of one or more electrodes, graphicaldepictions of a human torso, images or graphical depictions of thepatient's torso, graphical depictions or actual images of implantedelectrodes and/or leads, etc. Further, the display apparatus 130, 170may include a liquid crystal display, an organic light-emitting diodescreen, a touchscreen, a cathode ray tube display, etc.

The processing programs or routines stored and/or executed by thecomputing apparatus 140 and the remote computing device 160 may includeprograms or routines for computational mathematics, matrix mathematics,decomposition algorithms, compression algorithms (e.g., data compressionalgorithms), calibration algorithms, image construction algorithms,signal processing algorithms (e.g., various filtering algorithms,Fourier transforms, fast Fourier transforms, etc.), standardizationalgorithms, comparison algorithms, vector mathematics, or any otherprocessing used to implement one or more exemplary methods and/orprocesses described herein. Data stored and/or used by the computingapparatus 140 and the remote computing device 160 may include, forexample, electrical signal/waveform data from the electrode apparatus110 (e.g., a plurality of QRS complexes), electrical activation timesfrom the electrode apparatus 110, cardiac sound/signal/waveform datafrom acoustic sensors, graphics (e.g., graphical elements, icons,buttons, windows, dialogs, pull-down menus, graphic areas, graphicregions, 3D graphics, etc.), graphical user interfaces, results from oneor more processing programs or routines employed according to thedisclosure herein (e.g., electrical signals, electrical heterogeneityinformation, etc.), or any other data that may be used for carrying outthe one and/or more processes or methods described herein.

In one or more embodiments, the exemplary systems, methods, andinterfaces may be implemented using one or more computer programsexecuted on programmable computers, such as computers that include, forexample, processing capabilities, data storage (e.g., volatile ornon-volatile memory and/or storage elements), input devices, and outputdevices. Program code and/or logic described herein may be applied toinput data to perform functionality described herein and generatedesired output information. The output information may be applied asinput to one or more other devices and/or methods as described herein oras would be applied in a known fashion.

The one or more programs used to implement the systems, methods, and/orinterfaces described herein may be provided using any programmablelanguage, e.g., a high-level procedural and/or object orientatedprogramming language that is suitable for communicating with a computersystem. Any such programs may, for example, be stored on any suitabledevice, e.g., a storage media, that is readable by a general or specialpurpose program running on a computer system (e.g., including processingapparatus) for configuring and operating the computer system when thesuitable device is read for performing the procedures described herein.In other words, at least in one embodiment, the exemplary systems,methods, and interfaces may be implemented using a computer readablestorage medium, configured with a computer program, where the storagemedium so configured causes the computer to operate in a specific andpredefined manner to perform functions described herein. Further, in atleast one embodiment, the exemplary systems, methods, and interfaces maybe described as being implemented by logic (e.g., object code) encodedin one or more non-transitory media that includes code for executionand, when executed by a processor or processing circuitry, is operableto perform operations such as the methods, processes, and/orfunctionality described herein.

The computing apparatus 140 and the remote computing device 160 may be,for example, any fixed or mobile computer system (e.g., a controller, amicrocontroller, a personal computer, minicomputer, tablet computer,etc.). The exact configurations of the computing apparatus 140 and theremote computing device 160 are not limiting, and essentially any devicecapable of providing suitable computing capabilities and controlcapabilities (e.g., signal analysis, mathematical functions such asmedians, modes, averages, maximum value determination, minimum valuedetermination, slope determination, minimum slope determination, maximumslope determination, graphics processing, etc.) may be used. Asdescribed herein, a digital file may be any medium (e.g., volatile ornon-volatile memory, a CD-ROM, a punch card, magnetic recordable tape,etc.) containing digital bits (e.g., encoded in binary, trinary, etc.)that may be readable and/or writeable by the computing apparatus 140 andthe remote computing device 160 described herein. Also, as describedherein, a file in user-readable format may be any representation of data(e.g., ASCII text, binary numbers, hexadecimal numbers, decimal numbers,graphically, etc.) presentable on any medium (e.g., paper, a display,etc.) readable and/or understandable by a user.

In view of the above, it will be readily apparent that the functionalityas described in one or more embodiments according to the presentdisclosure may be implemented in any manner as would be known to oneskilled in the art. As such, the computer language, the computer system,or any other software/hardware which is to be used to implement theprocesses described herein shall not be limiting on the scope of thesystems, processes, or programs (e.g., the functionality provided bysuch systems, processes, or programs) described herein.

The exemplary electrode apparatus 110 may be configured to measurebody-surface potentials of a patient 14 and, more particularly,torso-surface potentials of a patient 14. As shown in FIG. 2, theexemplary electrode apparatus 110 may include a set, or array, ofexternal electrodes 112, a strap 113, and interface/amplifier circuitry116. The electrodes 112 may be attached, or coupled, to the strap 113and the strap 113 may be configured to be wrapped around the torso of apatient 14 such that the electrodes 112 surround the patient's heart. Asfurther illustrated, the electrodes 112 may be positioned around thecircumference of a patient 14, including the posterior, lateral,posterolateral, anterolateral, and anterior locations of the torso of apatient 14.

The exemplary electrode apparatus 110 may be further configured tomeasure, or monitor, sounds from at least one or both the patient 14. Asshown in FIG. 2, the exemplary electrode apparatus 110 may include aset, or array, of acoustic sensors 120 attached, or coupled, to thestrap 113. The strap 113 may be configured to be wrapped around thetorso of a patient 14 such that the acoustic sensors 120 surround thepatient's heart. As further illustrated, the acoustic sensors 120 may bepositioned around the circumference of a patient 14, including theposterior, lateral, posterolateral, anterolateral, and anteriorlocations of the torso of a patient 14.

Further, the electrodes 112 and the acoustic sensors 120 may beelectrically connected to interface/amplifier circuitry 116 via wiredconnection 118. The interface/amplifier circuitry 116 may be configuredto amplify the signals from the electrodes 112 and the acoustic sensors120 and provide the signals to one or both of the computing apparatus140 and the remote computing device 160. Other exemplary systems may usea wireless connection to transmit the signals sensed by electrodes 112and the acoustic sensors 120 to the interface/amplifier circuitry 116and, in turn, to one or both of the computing apparatus 140 and theremote computing device 160, e.g., as channels of data. In one or moreembodiments, the interface/amplifier circuitry 116 may be electricallycoupled to the computing apparatus 140 using, e.g., analog electricalconnections, digital electrical connections, wireless connections,bus-based connections, network-based connections, internet-basedconnections, etc.

Although in the example of FIG. 2 the electrode apparatus 110 includes astrap 113, in other examples any of a variety of mechanisms, e.g., tapeor adhesives, may be employed to aid in the spacing and placement ofelectrodes 112 and the acoustic sensors 120. In some examples, the strap113 may include an elastic band, strip of tape, or cloth. Further, insome examples, the strap 113 may be part of, or integrated with, a pieceof clothing such as, e.g., a t-shirt. In other examples, the electrodes112 and the acoustic sensors 120 may be placed individually on the torsoof a patient 14. Further, in other examples, one or both of theelectrodes 112 (e.g., arranged in an array) and the acoustic sensors 120(e.g., also arranged in an array) may be part of, or located within,patches, vests, and/or other manners of securing the electrodes 112 andthe acoustic sensors 120 to the torso of the patient 14. Still further,in other examples, one or both of the electrodes 112 and the acousticsensors 120 may be part of, or located within, two sections of materialor two patches. One of the two patches may be located on the anteriorside of the torso of the patient 14 (to, e.g., monitor electricalsignals representative of the anterior side of the patient's heart,measure surrogate cardiac electrical activation times representative ofthe anterior side of the patient's heart, monitor or measure sounds ofthe anterior side of the patient, etc.) and the other patch may belocated on the posterior side of the torso of the patient 14 (to, e.g.,monitor electrical signals representative of the posterior side of thepatient's heart, measure surrogate cardiac electrical activation timesrepresentative of the posterior side of the patient's heart, monitor ormeasure sounds of the posterior side of the patient, etc.). And stillfurther, in other examples, one or both of the electrodes 112 and theacoustic sensors 120 may be arranged in a top row and bottom row thatextend from the anterior side of the patient 14 across the left side ofthe patient 14 to the anterior side of the patient 14. Yet stillfurther, in other examples, one or both of the electrodes 112 and theacoustic sensors 120 may be arranged in a curve around the armpit areaand may have an electrode/sensor-density that less dense on the rightthorax that the other remaining areas.

The electrodes 112 may be configured to surround the heart of thepatient 14 and record, or monitor, the electrical signals associatedwith the depolarization and repolarization of the heart after thesignals have propagated through the torso of a patient 14. Each of theelectrodes 112 may be used in a unipolar configuration to sense thetorso-surface potentials that reflect the cardiac signals. Theinterface/amplifier circuitry 116 may also be coupled to a return orindifferent electrode (not shown) that may be used in combination witheach electrode 112 for unipolar sensing.

In some examples, there may be about 12 to about 50 electrodes 112 andabout 12 to about 50 acoustic sensors 120 spatially distributed aroundthe torso of a patient. Other configurations may have more or fewerelectrodes 112 and more or fewer acoustic sensors 120. It is to beunderstood that the electrodes 112 and acoustic sensors 120 may not bearranged or distributed in an array extending all the way around orcompletely around the patient 14. Instead, the electrodes 112 andacoustic sensors 120 may be arranged in an array that extends only partof the way or partially around the patient 14. For example, theelectrodes 112 and acoustic sensors 120 may be distributed on theanterior, posterior, and left sides of the patient with less or noelectrodes and acoustic sensors proximate the right side (includingposterior and anterior regions of the right side of the patient).

The computing apparatus 140 may record and analyze the torso-surfacepotential signals sensed by electrodes 112 and the sound signals sensedby the acoustic sensors 120, which are amplified/conditioned by theinterface/amplifier circuitry 116. The computing apparatus 140 may beconfigured to analyze the electrical signals from the electrodes 112 toprovide electrocardiogram (ECG) signals, information, or data from thepatient's heart as will be further described herein. The computingapparatus 140 may be configured to analyze the electrical signals fromthe acoustic sensors 120 to provide sound signals, information, or datafrom the patient's body and/or devices implanted therein (such as a leftventricular assist device).

Additionally, the computing apparatus 140 and the remote computingdevice 160 may be configured to provide graphical user interfaces 132,172 depicting various information related to the electrode apparatus 110and the data gathered, or sensed, using the electrode apparatus 110. Forexample, the graphical user interfaces 132, 172 may depict ECGsincluding QRS complexes obtained using the electrode apparatus 110 andsound data including sound waves obtained using the acoustic sensors 120as well as other information related thereto. Exemplary systems andmethods may noninvasively use the electrical information collected usingthe electrode apparatus 110 and the sound information collected usingthe acoustic sensors 120 to evaluate a patient's cardiac health and toevaluate and configure cardiac therapy being delivered to the patient.

Further, the electrode apparatus 110 may further include referenceelectrodes and/or drive electrodes to be, e.g. positioned about thelower torso of the patient 14, that may be further used by the system100. For example, the electrode apparatus 110 may include threereference electrodes, and the signals from the three referenceelectrodes may be combined to provide a reference signal. Further, theelectrode apparatus 110 may use of three caudal reference electrodes(e.g., instead of standard references used in a Wilson Central Terminal)to get a “true” unipolar signal with lesser noise from averaging threecaudally located reference signals.

FIG. 3 illustrates another exemplary electrode apparatus 110 thatincludes a plurality of electrodes 112 configured to surround the heartof the patient 14 and record, or monitor, the electrical signalsassociated with the depolarization and repolarization of the heart afterthe signals have propagated through the torso of the patient 14 and aplurality of acoustic sensors 120 configured to surround the heart ofthe patient 14 and record, or monitor, the sound signals associated withthe heart and/or an implanted device such as the LVAD after the signalshave propagated through the torso of the patient 14. The electrodeapparatus 110 may include a vest 114 upon which the plurality ofelectrodes 112 and the plurality of acoustic sensors 120 may beattached, or to which the electrodes 112 and the acoustic sensors 120may be coupled. In at least one embodiment, the plurality, or array, ofelectrodes 112 may be used to collect electrical information such as,e.g., surrogate electrical activation times. Similar to the electrodeapparatus 110 of FIG. 2, the electrode apparatus 110 of FIG. 3 mayinclude interface/amplifier circuitry 116 electrically coupled to eachof the electrodes 112 and the acoustic sensors 120 through a wiredconnection 118 and be configured to transmit signals from the electrodes112 and the acoustic sensors 120 to computing apparatus 140. Asillustrated, the electrodes 112 and the acoustic sensors 120 may bedistributed over the torso of a patient 14, including, for example, theposterior, lateral, posterolateral, anterolateral, and anteriorlocations of the torso of a patient 14.

The vest 114 may be formed of fabric with the electrodes 112 and theacoustic sensors 120 attached to the fabric. The vest 114 may beconfigured to maintain the position and spacing of electrodes 112 andthe acoustic sensors 120 on the torso of the patient 14. Further, thevest 114 may be marked to assist in determining the location of theelectrodes 112 and the acoustic sensors 120 on the surface of the torsoof the patient 14. In some examples, there may be about 25 to about 256electrodes 112 and about 25 to about 256 acoustic sensors 120distributed around the torso of the patient 14, though otherconfigurations may have more or fewer electrodes 112 and more or feweracoustic sensors 120.

The exemplary systems and methods may be used to provide noninvasiveassistance to a user in the evaluation of a patient's cardiac healthand/or evaluation and configuration of cardiac therapy beingpresently-delivered to the patient (e.g., by an implantable medicaldevice, by a LVAD, etc.). For example, the exemplary systems and methodsmay be used to assist a user in the configuration and/or adjustment ofone or more cardiac therapy settings such as, e.g., optimization of theA-V interval, or delay, of pacing therapy (e.g., left univentricularpacing therapy). Further, for example, the exemplary systems and methodsmay be used to assist a user in the configuration and/or adjustment ofone or more cardiac therapy settings for LVAD-delivered cardiac therapy.

Further, it is to be understood that the computing apparatus 140 and theremote computing device 160 may be operatively coupled to each other ina plurality of different ways so as to perform, or execute, thefunctionality described herein. For example, in the embodiment depicted,the computing device 140 may be wireless operably coupled to the remotecomputing device 160 as depicted by the wireless signal lines emanatingtherebetween. Additionally, as opposed to wireless connections, one ormore of the computing apparatus 140 and the remoting computing device160 may be operably coupled through one or wired electrical connections.

Illustrative graphical user interfaces that may be used to monitorinformation related to or gathered using the electrode apparatus (e.g.,external electrodes about a patient's torso) described herein aredepicted in FIGS. 4-8. For example, each of the graphical userinterfaces of FIGS. 4-8 may be displayed, or depicted, on the graphicaluser interfaces 132, 172 of the displays 130, 170 of the computingapparatus 140 and the remote computing device 150.

An illustrative graphical user interface 200 depicting electrode statusinformation is depicted in FIG. 4. The graphical user interface 200 mayinclude, among other things, a graphical electrode map 202 depictinginformation related to each of the physical electrodes of the electrodeapparatus described herein with respect to FIGS. 1-3. More specifically,in this embodiment, the graphical electrode map 202 includes a pluralityof electrode graphical elements 204 (some which are labeled in FIG. 4)corresponding to and positioned on the graphical map 202 in relation tothe physical location of the physical electrodes located proximate thepatient's skin. Although, in this embodiment, each electrode graphicalelement 204 is generally represented by a circle, it is to be understoodthat different graphics, or graphical representations, may be used torepresent each physical electrode.

Each electrode graphical 204 may include a number within a circle, whichmay correspond to a number printed on each of the physical electrodes.As shown, the graphical electrode elements 204 are numbered one throughforty. Further, the graphical electrode map 204 may further include oneor more graphical reference electrode elements 209 that correspond tophysical reference electrodes. As shown, four graphical referenceelectrode elements 209 are depicted on the graphical electrode map 202:more specifically, an anterior right side graphical reference electrodeelement, an anterior left side graphical reference electrode element, aposterior right side graphical reference electrode element, and aposterior right side graphical reference electrode element.

In this embodiment, the graphical electrode map 202 may extend from aleft portion 210 to a right portion 212. A middle portion 211 may belocated between the left portion 210 and the right portion 212. The leftportion 210 may correspond to the anterior side of the patient, theright portion 212 may correspond to the posterior side of the patient,and the middle portion 211 may correspond to the left side of thepatient. In other words, the graphical map 202 visually represent thephysical electrodes wrapping around the patient from the anterior to thepatient's left side to the patient's posterior.

Each electrode graphical element 204 may correspond to a physicalelectrode of the electrode apparatus described herein with respect toFIGS. 1-3. Due to various reasons (e.g., malfunction, poor contact,etc.), the physical electrodes may not provide an adequate, oracceptable, signal to be effectively used to derive electrical activityfrom the patient to be used in cardiac evaluation and cardiac therapyevaluation and adjustment. Each electrode graphical element 204 as wellas the reference electrode graphical elements 209 may provide aneffectiveness value proximate thereto to, for example, indicate orrepresent the effectiveness of the corresponding physical electrode inproviding a valid sensing signal from the tissue of the patient.

In this embodiment, each electrode graphical element 204 may have one ofthree different effectiveness values. In other words, each of theelectrode graphical elements may have one of three states to indicatethe effectiveness of the corresponding physical electrode in providing avalid sensing signal from the tissue of the patient. A physicalelectrode that is not in contact with tissue so as to not provide avalid sensing signal may be represented by a dotted-line circle and anexclamation mark positioned within the dotted-line circle. A physicalelectrode that is in contact with tissue but provides a poor signal sohas to not provide a valid sensing signal may be represented by adashed-line circle and a question mark positioned within the dashed-linecircle. A physical electrode that is in contact with tissue so as toprovide a valid sensing signal may be represented by a solid-linecircle. As shown, electrodes 3 and 14 have poor signal, and thus, thecorresponding electrode graphical elements 204 are dashed-line circleswith a question mark positioned within the dashed-line circles. Further,electrodes 13 and 39 are not in contact (e.g., no signal), and thus, thecorresponding electrode graphical elements 204 are dotted-line circleswith an exclamation mark positioned within the dotted-line circles.

In other embodiments, the effectiveness values may be represented usingdifferent graphics, or graphical representations, or using differentcolors or animations. For example, a physical electrode that is not incontact with tissue so as to not provide a valid sensing signal may berepresented by a red circle, a physical electrode that is in contactwith tissue but provides a poor signal so as to not provide a validsensing signal may be represented by a yellow circle, and a physicalelectrode that is in contact with tissue so as to provide a validsensing signal may be represented by a green circle.

In one example, more specifically, determination of the ECG signals thatshould be flagged as “red” or “yellow” on the system status screen maybe accomplished by creating a series of 1-second windows and removingany signals that are “lead off” per the amplifier at any measured pointduring a 1-second window. If they are “lead off” in at least 2 of 3consecutive windows, then such signals may be flagged as “red.” Next,the remaining signals may be de-trended using various processes. Then,within each 1-second window, any signals with peak-to-peak amplitude<0.12 millivolts (mV) may be removed and flagged as “potential yellow.”Further, the standard deviation across all remaining signals at eachtime point may be calculated, and the standard deviation slope at eachtime point=absolute value difference between successive standarddeviations may also be calculated. Using a 200 ms rolling window, thearea under the curve of the standard deviation slopes may be determined,and 200 ms window with the minimum area under the curve may beidentified or found. Within the 200 ms window, a rolling 100 ms windowmay be used to calculate the area under the curve of the standarddeviation slopes, and the 100 ms window with the minimum area under thecurve may be identified or found. Still further, the peak-to-peakamplitude of each signal in the 100 ms window may be calculated, and anyremaining signals with peak-to-peak amplitude >2.5*median peak-to-peakamplitude may be flagged as “potential yellow.” For each series of 3consecutive windows, the remaining signals flagged as “potential yellow”may be identified in at least 2 windows and flagged as “yellow.”

Further, determination of whether the electrode status is acceptable forrecording and calculating metrics/activation maps may be accomplishedthrough the following processes. First, exclude any electrode that isindicated as “lead off” or poor signal. Second, exclude any electrodewhere both neighbors were excluded in the first step. Third, if any ofthe following conditions are true, electrode contact is “unacceptable”:any reference electrode or the drive electrode is indicated as“lead-off” per the amplifier; more than two of electrodes 1-4 and 37-40are excluded; more than two of electrodes 5-8 and 33-36 are excluded;more than two of electrodes 9-12 and 29-32 are excluded; more than twoof electrodes 13-16 and 25-28 are excluded; more than two of electrodes17-24 are excluded; more than one of electrodes 33-37 are excluded. Ifnone of those conditions are true the electrode contact for the systemmay be considered “acceptable.”

A key 205 may be provided on the graphical user interface 200 proximatethe graphical electrode map 202 to provide examples of the variouseffectiveness values, or states, of the electrode graphical elements204. As shown, the key 205 includes one of each of differenteffectiveness values in this example: not in contact, poor signal, andgood signal.

The graphical electrode map 202 may further include, or define, one ormore principle electrodes graphical regions 220 to indicate which of theelectrode graphical elements 204 correspond to physical electrodes thatare considered to be the most principle electrodes (e.g., importantelectrodes, critical electrodes, etc.). In this example, the principleelectrodes graphical regions 220 may include a cross-hatched, or shaded,background about the electrode graphical elements 204 corresponding tothe most significant electrodes. In other words, the principalelectrodes graphical regions 220 may be referred to as criticalelectrodes regions to indicate which of the physical electrodes may becritical to obtaining electrical activity signals, or data, from thepatient to evaluate the patient's cardiac health and cardiac therapybeing delivered to the patient.

As shown, the principle electrodes graphical region 220 has identifiedfive electrode graphical elements 204 corresponding to physicalelectrodes positioned proximate the patient's left-central anterior.These physical electrodes may be determined to be significant becausethey provide the most significant electrical signals from the patientfor use in evaluating the patient's cardiac health and cardiac therapybeing delivered to the patient. The key 205, as shown, may furtherprovide an example of the principle electrode regions. In this example,the principle electrode regions may be referred to as “CriticalElectrodes.” In one or more embodiments, one or more (e.g., all) of theplurality of reference electrodes may be considered to be principleelectrodes, and thus, a principle electrodes graphical region 220 may bepositioned about the reference electrode graphical elements 209.

Additionally, the illustrative graphical user interface 200 may includea global electrode connection status message 222 indicative of the stateof the plurality of physical electrodes providing valid sensing signalfrom the tissue of the patient. The global electrode connection statusmessage 222 may be generated by determining how many of the physicalelectrodes are providing a good signal versus how many of the physicalelectrodes are providing a poor signal or are not in contact. If aselected number of the physical electrodes are determined as providing agood signal, the global electrode connection status message 222 mayprovide a message such as, e.g., “Good Contact” and a checkmark within acircle. As shown, if a selected number of the physical electrodes aredetermined as not providing a good signal, the global electrodeconnection status message 222 may provide a message such as, e.g.,“Issues Found” and a “X” within a circle. Still further, theillustrative graphical user interface 200 may include an amplifierstatus indicator 224. As shown, the amplifier status indicator 224 has acheckmark within a circle to indicate that the amplifier is connectedand working properly.

Illustrative graphical user interfaces 250 depicting, among otherthings, a graphical map of electrical activation 252 are shown in FIGS.5A-5C. In one or more embodiments, the graphical map of electricalactivation 252 may be a color-coded, or gray-scaled, two-dimensional maprepresenting the electrical activation about a portion of the surface ofa patient's torso. In the example depict in FIGS. 5A-5C, the graphicalmap of electrical activation 252 includes an anterior area 254 depictingthe activation times measured about the anterior torso of the patientand a posterior area 256 depicting the activation times measured aboutthe posterior torso of the patient.

The electrical activation data depicted on the graphical map ofelectrical activation 252 may be referred to as surrogate electricalactivation data (e.g., surrogate electrical activation times, surrogateelectrical activation time maps, etc.) and may be defined as datarepresentative of actual, or local, electrical activation data of one ormore regions of the patient's heart. For example, electrical signalsmeasured at the left anterior surface location of a patient's torso maybe representative, or surrogates, of electrical signals of the leftanterior left ventricle region of the patient's heart, electricalsignals measured at the left lateral surface location of a patient'storso may be representative, or surrogates, of electrical signals of theleft lateral left ventricle region of the patient's heart, electricalsignals measured at the left posterolateral surface location of apatient's torso may be representative, or surrogates, of electricalsignals of the posterolateral left ventricle region of the patient'sheart, and electrical signals measured at the posterior surface locationof a patient's torso may be representative, or surrogates, of electricalsignals of the posterior left ventricle region of the patient's heart.

The graphical map of electrical activation 252 may be further describedas extending from a left portion corresponding to anterior side of thepatient to a middle portion corresponding to the left side of thepatient to a right portion corresponding to the posterior side of thepatient. The right side of the anterior area 254 may correspond to theleft anterior region of the torso of the patient, and the left side ofthe anterior area 254 may correspond to the right anterior region of thetorso of the patient. Thus, the electrical signal data such aselectrical activation measured from the right anterior region of thetorso of the patient (e.g., using electrodes positioned on the rightanterior region of the torso of the patient) may be depicted on leftside of the anterior area 254, and the electrical signal data such aselectrical activation measured from the left anterior region of thetorso of the patient (e.g., using electrodes positioned on the leftanterior region of the torso of the patient) may be depicted on rightside of the anterior area 254.

The right side of the posterior area 256 may correspond to the rightposterior region of the torso of the patient, and the left side of theposterior area 256 may correspond to the left posterior region of thetorso of the patient. Thus, the electrical signal data such aselectrical activation measured from the right posterior region of thetorso of the patient (e.g., using electrodes positioned on the rightposterior region of the torso of the patient) may be depicted on rightside of the posterior area 256, and the electrical signal data such aselectrical activation measured from the left posterior region of thetorso of the patient (e.g., using electrodes positioned on the leftposterior region of the torso of the patient) may be depicted on leftside of the posterior area 256.

The graphical map of electrical activation 252 may further include anelectrical activation key 259 for use in interpreting, or decoding, theanterior and posterior areas 254, 256 of electrical activation. Asshown, the electrical activation key 259 may be a color-coded, orgray-scaled, in the same way as the anterior and posterior areas 254,256.

Further, the graphical user interfaces 250 may include, or depict, aplurality of electrode signals 260 over a plurality of cardiac cycles.More specifically, as shown, the plurality of electrode signals 260 maybe described as being graphed, or plotted, over time where the y-axisrepresents voltage of the electrode signals 260 and the x-axisrepresents time in milliseconds. The electrode signals 260 may beplotted for a plurality of cardiac cycles (e.g., continuous cardiaccycles), each of which may be numerically labeled. As shown, fivecardiac cycles number one through 5 are depicted. Additionally, thecardiac cycles may be plotted over a selected time period regardless ofhow many cardiac cycles occur within the selected time period. In oneembodiment, the selected time period may be five seconds.

A cardiac cycle, or beat, may be selected, and the selected cardiaccycle may be indicated as being selected within the plurality ofelectrodes signals 260 over the plurality of cardiac cycles. In thisexample, the selected cardiac cycle is indicated by being bounded by apair of solid vertical lines 262 (e.g., shown between red calipers). Inone or more embodiments the solid vertical lines 262 may represent orcorrespond to the onset and offset of the selected cardiac cycle (e.g.,QRS onset/offset). The cardiac cycle may be automatically selected bythe illustrative systems and process described herein, e.g., selected tobe the best representation of useful data. As shown, cardiac cycle “2”has been automatically selected as indicated by the word “Auto” in thecardiac cycle selection region 264. In one or more embodiments, thecardiac cycle that is determined to be most typical, or morerepresentative, of the patient's cardiac health or status may beselected. Automatic cardiac cycle selection may be described in U.S.Provisional Patent Application. Ser. No. 62/538,337 filed on Jul. 28,2017, and entitled “Cardiac Cycle Selection,” which is hereinincorporated by reference in its entirety.

The cardiac cycle selection region 264 may be further used by a user toselect one of the cardiac cycles of plurality of electrode signals 260.For example, a user may select (e.g., click, touch, etc.) the cardiaccycle selection region 264, which may then display a dialog include theremaining cardiac cycles that may be selectable by a user. If a newcardiac cycle is selected, the new cardiac cycle may be indicated asbeing selected within the cardiac cycle selection region 264 in the sameway as the previously selected cardiac cycle (e.g., bounded by a pair ofsolid vertical lines). It is to be understood that this embodiment isone example of cardiac cycle selection and indication and that othergraphical dialogs, regions, and areas may be used to select a cardiaccycle. For example, in one embodiment, a user may select a cardiac cycleby selecting (e.g., click, touch, etc.) the cardiac cycle, or thenumerical identifier corresponding thereto, on the graphicalrepresentation of the plurality of electrode signals 260 on thegraphical user interface 250. In other words, a user may directly selectcardiac cycle on the graph depicting the cardiac cycles.

The graphical map of electrical activation 252 corresponds to theelectrical activation of the selected cardiac cycle. Thus, in thisexample, the graphical map of electrical activation 252 corresponds tothe electrical activation of cardiac cycle “2.” If another cardiac cyclewere selected by a user using the cardiac cycle selection region 264 orautomatically by the systems and methods described herein, the graphicalmap of electrical activation 252 depicted on the graphical userinterface 250 will change so as to correspond to the electricalactivation of the newly selected cardiac cycle. In other words, thegraphical map of electrical activation 252 may be displayed based on themonitored electrical activity for the selected cardiac cycle.

As shown in FIG. 5B, the graphical user interface 250 may be furtherconfigured to display a plurality of electrode elements 272corresponding to and positioned on the graphical map of electricalactivation 252 in relation to the physical location of the plurality ofelectrodes located proximate the patient's skin (which, e.g., are usedto capture electrical activation data displayed on the graphical map252). As shown in this example, the plurality of electrode elements 272are alphanumeric characters (e.g., numbers) identifying the electrodes.The electrodes attached, or coupled, to the patient may also benumbered, which may correspond to the electrode elements 272.

The electrode elements 272 may be displayed by a user selecting anelectrode element display region 270 of the graphical user interface 250as shown in FIG. 5A. When the electrode elements 272 are displayed asshown in FIG. 5B, the electrode element display region 270 may beselected to hide the electrode elements 272 (e.g., return to theinterface 250 of FIG. 5A). In other words, the exemplary systems,methods, and interfaces may allow a user to hide or display theplurality of electrode elements 272 using, e.g., the electrode elementdisplay region 270.

Additionally, which of the plurality of electrode elements 272corresponds to electrodes that are ineffective in providing a validsensing signal from the tissue of the patient may be graphicallyindicated within the graphical map of electrical activation 252. In theexample depicted in FIG. 5B, the ineffective electrode elements 274 thatcorrespond to ineffective electrodes are a different color from theelectrode elements 272 that are effective. Further, the electrodeelements 274 that correspond to ineffective electrodes are encircled bya box. In this way, a user may be able to quickly identify which of theplurality of electrodes are ineffective and effective, and where withinthe graphical map of electrical activation 252 such electrode effectiveor ineffective electrode signals are derived from. As shown, electrodes3, 13, 14, and 39 are indicated as being ineffective, which correspondsto the interface 200 of FIG. 4 where electrodes 13 and 39 were not incontact and electrodes 3 and 14 had poor signal.

Further, when electrodes, and therefore, the electrode signals derivedtherefrom are determined to be ineffective, the exemplary systems,methods, and interfaces described herein may be configured tointerpolate the electrical activation of each area of the graphical map252 of electrical activation corresponding to such ineffective externalelectrodes. Thus, when used in conjunction with the depiction ofineffective electrode elements 274, a user may ascertain that theelectrical activation depiction on the graphical map 252 correspondingto ineffective electrode elements 274 may not be based on actual,measured electrical activation at that location, and instead, may bebased on interpolated data from effective electrode signals proximate tothe ineffective electrodes.

More specifically, the activation maps may be created by interpolating a2-by-20 matrix of activation times by first using an inversedistance-weighted interpolation step followed by a two-dimensionalbi-cubic interpolation method. Further, for each electrode (e.g.,iterated over all electrodes), (a) if an electrode is marked as valid,the activation time is directly used in the bi-cubic interpolation stepor (b) if an electrode is marked as invalid, find all valid electrodeswithin the same belt plane (anterior or posterior). The contribution ofeach valid electrode to the interpolation is its activation time valuemay be weighted by the inverse of the distance squared from the invalidelectrode using the following:

${AT}_{invalid} = {\sum\limits_{k = 1}^{N}\frac{\left( \frac{1}{{dist}_{k}} \right)^{2} \times {AT}_{k,{valid}}}{\left( \frac{1}{{dist}_{k}} \right)^{2}}}$Where${dist}_{k} = \sqrt{\left( {x_{invalid} - x_{k,{valid}}} \right)^{2} + \left( {y_{invalid} - y_{k,{valid}}} \right)^{2}}$

Next, using the 2×20 array of activation times, for each set of 2×2neighboring points that form a ‘unit square’, a system of 16 equationsmay be solved to find 16 coefficients of a two-dimensional polynomialfunction that can find the interpolated value at any fractional partwithin the unit square. Then, such processes may be repeated for allpossible neighboring 2×2 point sets.

In one or more embodiments, one or more areas of conduction block may bedepicted on the graphical map of electrical activation 252 based on themonitored electrical activity for the selected cardiac cycle. Forexample, the conduction block may be indicated by a thick colored lineon the graphical map of electrical activation 252. In other embodiments,the conduction block may be represented by a “break” in the graphicalmap of electrical activation 252. For example, different portions orareas of the graphical map of electrical activation 252 may be split offfrom one another such that a space or gap exists between the split offportions or areas.

The graphical user interface 250 may further display at least one metricof electrical heterogeneity 271 based on the monitored electricalactivity for the selected cardiac cycle. As shown, the metrics ofelectrical heterogeneity 271 depicted are SDAT and LVAT. The SDAT may bedefined as the global standard deviation of surrogate electricalactivation times monitored by a plurality of external electrodes. TheLVAT may be defined as an average of electrical activation timesmonitored by two or more left external electrodes (e.g., two or moreleft external electrodes configured to be located proximate the leftside of the patient).

A user may desire to more closely view the selected cardiac cycle of theplurality of electrode signals 262. Thus, the interface 250 may befurther configured to depict an enlarged graphical region 280 depictinga single cardiac cycle. Similar to as shown in FIGS. 5A-5B the enlargedgraphical region 280 depicts the plurality of electrode signals 260 anda pair of solid vertical lines 262 bounding, or identifying, theselected cardiac cycle, which in this example is cardiac cycle “2.”Further, in one or more embodiments the solid vertical lines 262 mayrepresent or correspond to the onset and offset of the selected cardiaccycle (e.g., QRS onset/offset). To display the enlarged graphical region280, a user may select the magnifying glass graphical element 282 asdepicted in FIGS. 5A-5B. To minimize, or close, the enlarged graphicalregion 280, a user may select the close graphical element 284 of theenlarged graphical region 280 depict in FIG. 5C, which will return theuser to the interface as provided in FIGS. 5A-5B.

The graphical user interface 250 may be further configured to depictmeasured electrical activity for a plurality of different cardiactherapy scenarios including no cardiac therapy delivered or intrinsicactivation. For example, as shown in FIGS. 5A-5B, the graphical userinterface 250 is depicting intrinsic cardiac electrical activation ofthe patient. In other words, no cardiac therapy was delivered to thepatient when the electrical signal data that is currently beingdisplayed was monitored or measured from the patient. The graphical userinterface 250 may include a cardiac therapy scenario graphical region290, which may be useable by a user to select none or one or morevarious cardiac therapy scenarios. For each different selected cardiactherapy scenario, the graphical user interface 250 may display theplurality of electrode signals 260 over a plurality of cardiac cyclescorresponding to the selected cardiac therapy scenario, and thegraphical map of electrical activation 252 will correspond to theselected cardiac cycle of the plurality of electrode signals 260 of, orcorresponding to, the selected cardiac therapy scenario.

For example, in FIGS. 5A-5B, the selected cardiac therapy scenario is“intrinsic” where no cardiac therapy (e.g., no cardiac resynchronizationtherapy) is being delivered to the patient, and thus, the plurality ofelectrode signals 260 and the graphical map of electrical activation 252are based on electrical activity measured, or monitored, without thedelivery of cardiac therapy (e.g., based on intrinsic activation).However, a user may select a different cardiac therapy scenario usingthe cardiac therapy scenario graphical region 290. For example, as shownin FIGS. 5A-5B, a user may select a RV-paced cardiac therapy scenario(e.g., also where no cardiac resynchronization therapy is beingdelivered).

An illustrative graphical user interface 250 depicting, among otherthings, a plurality of electrode signals 260, a graphical map ofelectrical activation 252, and a cardiac therapy scenario selectionregion 290 where cardiac therapy has been selected is depicted in FIG.6. As shown, a cardiac therapy scenario has been selected in thisembodiment, and more specifically, cardiac therapy has been selectedwhere the LV-RV, or V-V, delay is 0 milliseconds (ms), the A-V delay is160 ms, and the pacing site is LV1 (e.g., a particular electrode of alead). Thus, the plurality of electrode signals 260 and the graphicalmap of electrical activation 252 correspond to the electrical datameasured, or monitored, from a patient during the selected cardiactherapy scenario, which as described in this example is cardiac therapythat utilizes a V-V delay of 0 ms, an A-V delay of 120 ms, and the LV1pacing site.

As shown in FIG. 6, the cardiac therapy scenario selection region 290may include a plurality of various cardiac therapy settings. In thisexample, the plurality of various cardiac therapy settings include atleast one of pacing configuration (e.g., RV-LV, LV-RV, LV only, RV only,etc.), V-V delay, A-V delay, LV pacing site, and adaptive cardiacresynchronization therapy (ACRT). In other examples, the plurality ofvarious cardiac therapy settings may include one or more of multipointpacing, LV-LV delay, etc.

In some embodiments, when a cardiac therapy scenario is changed ormodified by a user, the delivered cardiac therapy may be changed in realtime, and the monitored electrical activity upon which the electricaldata depicted in the graphical user interface 250 may be updated in realtime. In other words, the systems, methods, and interfaces describedherein may provide adjustment of cardiac therapy and real-time feedbackfrom such adjustment of cardiac therapy.

In other embodiments, the electrical data may be measured and recordedfor each of the plurality of different cardiac therapy scenarios, andwhen a user selects a cardiac therapy scenario, the electrical datadepicted in the graphical user interface 250 may be updated based on thedata measured and recorded previously using the selected cardiac therapyscenario. In other words, the systems, methods, and interfaces describedherein may provide evaluation of a plurality of different cardiactherapy scenarios after such data for such different cardiac therapyscenarios has been monitored and recorded.

Additionally, the illustrative systems, methods, and interfaces may be ahybrid of both systems where the data for a cardiac therapy scenario maybe monitored and displayed in real time while the cardiac therapy isbeing adjusted, and then optionally recorded and saved for laterviewing. For example, the graphical user interface 250 may include arecord and save graphical elements 295 that may be used to record andsave monitored electrical activity for a particular cardiac therapyscenario and a view saved scenario graphical region 296 that may be usedto select previously recorded and saved electrical activation data for aparticular cardiac therapy scenario. In particular, the record graphicalelement may initiate the recording of a patient's electrical activationusing the external electrode apparatus over a selected time period suchas five seconds, and the save graphical element may allow such recordeddata to be saved for use in further analysis. As shown, the view savedscenario graphical region 296 includes one cardiac therapy scenario:namely, intrinsic. Selection of the intrinsic cardiac therapy scenariomay depict, or display, the electrical activation data of FIGS. 5A-5B.

As noted herein, the cardiac cycle (e.g., from which the graphical mapof electrical activation 252 and metrics of electrical heterogeneity 271are derived from) may be automatically selected by the illustrativesystems and methods. In one embodiment, selecting one cardiac cycle ofthe plurality of cardiac cycles may include selecting the cardiac cycleof the plurality of cardiac cycles having characteristics (e.g., median,minimum, maximum, and/or summed signal amplitude characteristics) thatrepresent the patient's typical or representative cardiac cycle.

Additionally, the illustrative graphical user interface 250 may includean electrode selection graphical region 285 that may be used by a userto select an electrode set of a plurality of different electrode sets ofthe plurality of external electrodes to be used for the measurement ofelectrical data for display on the graphical user interface 250. Forexample, the plurality of electrode signals 260 over the plurality ofcardiac cycles that is displayed may only include electrode signals ofthe selected electrode set, and the displayed graphical map ofelectrical activation 252 may be based on the monitored electricalactivity from only electrode signals of the selected electrode set. Theelectrode sets may include all valid signals, which as shown in FIGS.5A-B & 6 is presently selected, and thus, all electrode signals wereused to generate the maps of electrical activation and calculate themetrics of electrical heterogeneity. In other embodiments, the electrodesets may include only anterior signals, only posterior signals, onlyleft anterior signals, only left posterior signals, only a subset of thesignals most proximate to the patient's heart, the signal most proximateto the V1 location of a standard 12-lead ECG, the signals covering thesame area but not the same pattern, etc.

An illustrative graphical user interface 300 depicting, among otherthings, a plurality of graphical maps of electrical activation fromexternal electrodes corresponding to different cardiac therapy scenariosis depicted in FIG. 7. Each of the plurality of graphical maps ofelectrical activation may correspond to a different cardiac therapyscenario of the plurality of different cardiac therapy scenarios thaneach other. Each of the graphical maps of the electrical activation ofgraphical user interface 300 may be similar to the graphical maps ofelectrical activation as described herein with respect to FIGS. 5A-5B &6. For example, each of the graphical maps of the electrical activationof the graphical user interface 300 may include an anterior areadepicting the activation times measured about the anterior torso of thepatient and a posterior area depicting the activation times measuredabout the posterior torso of the patient, and may extend from the rightanterior to the left anterior to the left side to the left posterior tothe right posterior. Further, the graphical user interface 300 mayinclude a plurality of metrics of electrical heterogeneity correspondingto the plurality of graphical maps of electrical activation. In thisexample, two metrics of electrical heterogeneity are displayed proximateand corresponding to each of the plurality of graphical maps ofelectrical activation. More specifically, SDAT and LVAT are displayedproximate and corresponding to each of the plurality of graphical mapsof electrical activation. Additionally, a percentage change of each ofthe metrics of electrical heterogeneity are displayed, or depicted,proximate the metrics. The percentage change may be the percentagechange from the metrics of electrical heterogeneity computed, ordetermined, from an intrinsic cardiac therapy scenario (where no cardiacresynchronization therapy is delivered). In other embodiments, thepercentage change may be the percentage change from the metrics ofelectrical heterogeneity computed, or determined, from a baselinecardiac therapy scenario (e.g., the cardiac therapy that may bedelivered to a patient prior to the present evaluation).

As shown, the graphical user interface 300 may include a graphical mapof intrinsic electrical activation 302 and a plurality of graphical mapsof paced electrical activation 304, each having a different cardiactherapy scenario associated therewith. Additionally, each of theplurality of graphical maps of paced electrical activation 304 may bearranged in accordance with the adjustment of the cardiac therapysettings. For example, when moving from left to right (e.g., from columnto column) and when moving from top to bottom (e.g., from row to row)one or more cardiac therapy settings may be adjusted or changed. In thisway, a user may be able to view the graphical user interface 300 andascertain which of the plurality of different cardiac therapy scenariosmay be beneficial (e.g., most beneficial) or effective for the patient.

In this illustrative embodiment, the first column may represent cardiactherapy scenarios having a V-V delay of 0 ms, the second column mayrepresent cardiac therapy scenarios having a V-V delay of 20 ms, thethird column may represent cardiac therapy scenarios having a V-V delayof 40 ms, and the fourth column may represent cardiac therapy scenarioshaving a V-V delay of 60 ms. Further, the first row may representcardiac therapy scenarios having a A-V delay of 120 ms, the second rowmay represent cardiac therapy scenarios having a A-V delay of 140 ms,the third row may represent cardiac therapy scenarios having a A-V delayof 160 ms, and the fourth row may represent cardiac therapy scenarioshaving a A-V delay of 180 ms. It is to be understood that the A-V andV-V delays used and shown in the column and rows of FIG. 7 is oneexample, and the disclosure herein contemplates other A-V and V-Vdelays. For example, A-V delays ranging from about 80 ms to about 240 msat steps of 20 ms and V-V delays ranging from about 0 ms to about 80 msat steps of 20 ms may be utilized. Additionally, the plurality ofgraphical maps of paced electrical activation 304 could be organized, orarranged, by LV pacing site or LV pacing vector (in the exampledepicted, the pacing site is always LV1).

Further, it may be described that the organization could be primarilydictated by V-V delay, secondarily by A-V delay, and tertiarily by LVpacing site or in a any other different order of priority. Also, aclinician could be provided a choice of different filtering options.

Still further, the graphical user interface 300 may include anelectrical activation key 312 for use in interpreting, or decoding, thegraphical maps of electrical activation. As shown, the electricalactivation key 312 may be a color-coded, or gray-scaled, in the same wayas the anterior and posterior areas of the graphical maps of electricalactivation. Still further, the graphical user interface 300 may includea create and save graphical region 310 configured for selection by auser to create and save a digital file of the data depicted, or shown,on the graphical user interface 300. In one example, the create and savegraphical region 310 may be used to generate a portable, printabledigital file that may be viewed consistently on many different types ofcomputers and printed consistently on many different types of printers.

The illustrative systems, methods, and interface described herein may beconfigured to evaluate and sort a plurality of different cardiac therapyscenarios based on the monitored electrical activation which wasobtained for each of different cardiac therapy scenarios. One or moremetrics of electrical heterogeneity, or electrical dyssynchrony, may beused by the evaluation and sorting of the cardiac therapy scenarios.

One illustrative evaluation and sorting graphical user interface 400 isdepicted in FIGS. 8A-8C. The graphical user interface 400 of FIG. 8Adepicts a cardiac therapy scenario selection region 402. The cardiactherapy scenario selection region 402 may be configured to allow a userto select one or more cardiac therapy scenarios that the illustrativesystems, methods, and interfaces may evaluate and sort. As shown, all ofthe available cardiac therapy scenarios (where electrical activationdata have been monitored, or collected, for use in cardiac therapyevaluation) are presently selected as indicated by the checkmarksbesides each of the cardiac therapy scenarios. A user may select ordeselect (e.g., clicking, touching, etc.) each of the cardiac therapyscenarios using the cardiac therapy scenario selection region 402, andafter a user has selected the cardiac therapy scenarios, the user mayselect the sort initiation region 405.

Selection of the sort initiation region 405 may initiate, or execute,the initial sorting of the cardiac therapy scenarios as shown in FIG.8B. The illustrative graphical user interface 400 of FIG. 8B depicts aranking of selected cardiac therapy scenarios that have been sorted, orranked, based on generated electrical heterogeneity informationgenerated for each of the selected cardiac therapy scenarios within asort graphical region 410. In one or more embodiments, the selectedcardiac therapy scenarios are ranked based on a primary metric ofelectrical heterogeneity. In this example, the primary metric ofelectrical heterogeneity may be SDAT. In another embodiment, the primarymetric of electrical heterogeneity may be LVAT. These metrics, or othermetrics of electrical heterogeneity, 412 for each of the selectedcardiac therapy scenarios may also be depicted in the sort graphicalregion 410 as well as the percentage change from baseline therapy orintrinsic activation.

In the event of a “tie,” the selected cardiac therapy scenarios may befurther ranked, or sorted, based on a secondary metric of electricalheterogeneity such as, e.g., SDAT or LVAT. In this embodiment, thesecondary metric of electrical heterogeneity may be LVAT. In otherwords, two or more of the selected cardiac therapy scenarios may befurther ranked based on a secondary metric of electrical heterogeneityif the primary metric of electrical heterogeneity of the two moreselected cardiac therapy scenarios are within a selected threshold, orrange, (e.g., 5%) from each other. In other words, for example, theranked order may be accomplished through the following steps using theSDAT and LVAT values for the selected pacing scenarios: rank the pacingscenarios in order of smallest to largest SDAT percent change values,assign a rank of 1 to all pacing scenarios within 3% of the smallestSDAT, and for all pacing scenarios with a ranking of 1, demote anypacing scenario with an LVAT percent change more than 30 percent greaterthan the minimum LVAT percentage change of the pacing scenarios ranked1.

Further, the graphical user interface 400 may be further configured todepict multiple sorts, or rankings, within the sort graphical region 410as shown in FIG. 8C. In particular, a plurality of rankings 415 of thedifferent groups of selected cardiac therapy scenarios may be depicted,or shown, in the sort graphical region 410. The plurality of rankings415 of the different groups of selected cardiac therapy scenarios may begenerated, and then displayed, by a user selecting different cardiactherapy scenarios using the cardiac therapy scenario selection region402, and then initiating another sort, or ranking, by selecting the sortinitiation region 405.

For example, as shown, the “Sort 3” has been generated by a userselecting two different cardiac therapy scenarios, namely, a firstcardiac therapy scenario having a V-V timing of 40 ms, A-V timing of 60ms, and a LV2 left ventricular pacing location and a second cardiactherapy scenario having a V-V timing of 80 ms, A-V timing of 100 ms, anda LV2 left ventricular pacing location. After selecting the sortinitiation region 405, such two cardiac therapy scenarios may be sortedaccording to a primary metric of electrical heterogeneity (e.g., SDAT),and in this example, the primary metric of electrical heterogeneity ofeach of the two cardiac therapy scenarios is within 1% of each other,and thus, the secondary metric of electrical heterogeneity (e.g., LVAT)of each of the two cardiac therapy scenarios may be used to completedthe sorting or ranking.

Exemplary cardiac therapy may be further described herein with referenceto FIGS. 9-11. Additionally, the exemplary systems and methods describedherein may further use or incorporated the systems and methods describedin U.S. Pat. App. Pub. No. 2016/0045737 to Ghosh et al. published onFeb. 18, 2016, U.S. Pat. App. Pub. No. 2016/0045738 to Ghosh et al.published on Feb. 18, 2016, U.S. Pat. App. Pub. No. 2016/0045744 toGillberg et al. published on Feb. 18, 2016, all of which areincorporated herein by reference in their entireties.

The exemplary systems, methods, and graphical user interfaces describedherein may be used with respect to the implantation and configuration ofan implantable medical device (IMD) and/or one or more leads configuredto be located proximate one or more portions of a patient's heart. Forexample, the exemplary systems, methods, and interfaces may be used inconjunction with an exemplary therapy system 10 described herein withreference to FIGS. 9-11.

FIG. 9 is a conceptual diagram illustrating an exemplary therapy system10 that may be used to deliver pacing therapy to a patient 14. Patient14 may, but not necessarily, be a human. The therapy system 10 mayinclude an implantable medical device 16 (IMD), which may be coupled toleads 18, 20, 22. The IMD 16 may be, e.g., an implantable pacemaker,cardioverter, and/or defibrillator, that delivers, or provides,electrical signals (e.g., paces, etc.) to and/or senses electricalsignals from the heart 12 of the patient 14 via electrodes coupled toone or more of the leads 18, 20, 22.

The leads 18, 20, 22 extend into the heart 12 of the patient 14 to senseelectrical activity of the heart 12 and/or to deliver electricalstimulation to the heart 12. In the example shown in FIG. 9, the rightventricular (RV) lead 18 extends through one or more veins (not shown),the superior vena cava (not shown), and the right atrium 26, and intothe right ventricle 28. The left ventricular (LV) coronary sinus lead 20extends through one or more veins, the vena cava, the right atrium 26,and into the coronary sinus 30 to a region adjacent to the free wall ofthe left ventricle 32 of the heart 12. The right atrial (RA) lead 22extends through one or more veins and the vena cava, and into the rightatrium 26 of the heart 12.

The IMD 16 may sense, among other things, electrical signals attendantto the depolarization and repolarization of the heart 12 via electrodescoupled to at least one of the leads 18, 20, 22. In some examples, theIMD 16 provides pacing therapy (e.g., pacing pulses) to the heart 12based on the electrical signals sensed within the heart 12. The IMD 16may be operable to adjust one or more parameters associated with thepacing therapy such as, e.g., AV delay and other various timings, pulsewide, amplitude, voltage, burst length, etc. Further, the IMD 16 may beoperable to use various electrode configurations to deliver pacingtherapy, which may be unipolar, bipolar, quadripoloar, or furthermultipolar. For example, a multipolar lead may include severalelectrodes that can be used for delivering pacing therapy. Hence, amultipolar lead system may provide, or offer, multiple electricalvectors to pace from. A pacing vector may include at least one cathode,which may be at least one electrode located on at least one lead, and atleast one anode, which may be at least one electrode located on at leastone lead (e.g., the same lead, or a different lead) and/or on thecasing, or can, of the IMD. While improvement in cardiac function as aresult of the pacing therapy may primarily depend on the cathode, theelectrical parameters like impedance, pacing threshold voltage, currentdrain, longevity, etc. may be more dependent on the pacing vector, whichincludes both the cathode and the anode. The IMD 16 may also providedefibrillation therapy and/or cardioversion therapy via electrodeslocated on at least one of the leads 18, 20, 22. Further, the IMD 16 maydetect arrhythmia of the heart 12, such as fibrillation of theventricles 28, 32, and deliver defibrillation therapy to the heart 12 inthe form of electrical pulses. In some examples, IMD 16 may beprogrammed to deliver a progression of therapies, e.g., pulses withincreasing energy levels, until a fibrillation of heart 12 is stopped.

FIGS. 10A-10B are conceptual diagrams illustrating the IMD 16 and theleads 18, 20, 22 of therapy system 10 of FIG. 9 in more detail. Theleads 18, 20, 22 may be electrically coupled to a therapy deliverymodule (e.g., for delivery of pacing therapy), a sensing module (e.g.,for sensing one or more signals from one or more electrodes), and/or anyother modules of the IMD 16 via a connector block 34. In some examples,the proximal ends of the leads 18, 20, 22 may include electricalcontacts that electrically couple to respective electrical contactswithin the connector block 34 of the IMD 16. In addition, in someexamples, the leads 18, 20, 22 may be mechanically coupled to theconnector block 34 with the aid of set screws, connection pins, oranother suitable mechanical coupling mechanism.

Each of the leads 18, 20, 22 includes an elongated insulative lead body,which may carry a number of conductors (e.g., concentric coiledconductors, straight conductors, etc.) separated from one another byinsulation (e.g., tubular insulative sheaths). In the illustratedexample, bipolar electrodes 40, 42 are located proximate to a distal endof the lead 18. In addition, bipolar electrodes 44, 45, 46, 47 arelocated proximate to a distal end of the lead 20 and bipolar electrodes48, 50 are located proximate to a distal end of the lead 22.

The electrodes 40, 44, 45, 46, 47, 48 may take the form of ringelectrodes, and the electrodes 42, 50 may take the form of extendablehelix tip electrodes mounted retractably within the insulative electrodeheads 52, 54, 56, respectively. Each of the electrodes 40, 42, 44, 45,46, 47, 48, 50 may be electrically coupled to a respective one of theconductors (e.g., coiled and/or straight) within the lead body of itsassociated lead 18, 20, 22, and thereby coupled to a respective one ofthe electrical contacts on the proximal end of the leads 18, 20, 22.

Additionally, electrodes 44, 45, 46 and 47 may have an electrode surfacearea of about 5.3 mm² to about 5.8 mm². Electrodes 44, 45, 46, and 47may also be referred to as LV1, LV2, LV3, and LV4, respectively. The LVelectrodes (i.e., left ventricle electrode 1 (LV1) 44, left ventricleelectrode 2 (LV2) 45, left ventricle electrode 3 (LV3) 46, and leftventricle 4 (LV4) 47 etc.) on the lead 20 can be spaced apart atvariable distances. For example, electrode 44 may be a distance of,e.g., about 21 millimeters (mm), away from electrode 45, electrodes 45and 46 may be spaced a distance of, e.g. about 1.3 mm to about 1.5 mm,away from each other, and electrodes 46 and 47 may be spaced a distanceof, e.g. 20 mm to about 21 mm, away from each other.

The electrodes 40, 42, 44, 45, 46, 47, 48, 50 may further be used tosense electrical signals (e.g., morphological waveforms withinelectrograms (EGM)) attendant to the depolarization and repolarizationof the heart 12. The electrical signals are conducted to the IMD 16 viathe respective leads 18, 20, 22. In some examples, the IMD 16 may alsodeliver pacing pulses via the electrodes 40, 42, 44, 45, 46, 47, 48, 50to cause depolarization of cardiac tissue of the patient's heart 12. Insome examples, as illustrated in FIG. 10A, the IMD 16 includes one ormore housing electrodes, such as housing electrode 58, which may beformed integrally with an outer surface of a housing 60 (e.g.,hermetically-sealed housing) of the IMD 16 or otherwise coupled to thehousing 60. Any of the electrodes 40, 42, 44, 45, 46, 47, 48, 50 may beused for unipolar sensing or pacing in combination with the housingelectrode 58. It is generally understood by those skilled in the artthat other electrodes can also be selected to define, or be used for,pacing and sensing vectors. Further, any of electrodes 40, 42, 44, 45,46, 47, 48, 50, 58, when not being used to deliver pacing therapy, maybe used to sense electrical activity during pacing therapy.

As described in further detail with reference to FIG. 10A, the housing60 may enclose a therapy delivery module that may include a stimulationgenerator for generating cardiac pacing pulses and defibrillation orcardioversion shocks, as well as a sensing module for monitoring theelectrical signals of the patient's heart (e.g., the patient's heartrhythm). The leads 18, 20, 22 may also include elongated electrodes 62,64, 66, respectively, which may take the form of a coil. The IMD 16 maydeliver defibrillation shocks to the heart 12 via any combination of theelongated electrodes 62, 64, 66 and the housing electrode 58. Theelectrodes 58, 62, 64, 66 may also be used to deliver cardioversionpulses to the heart 12. Further, the electrodes 62, 64, 66 may befabricated from any suitable electrically conductive material, such as,but not limited to, platinum, platinum alloy, and/or other materialsknown to be usable in implantable defibrillation electrodes. Sinceelectrodes 62, 64, 66 are not generally configured to deliver pacingtherapy, any of electrodes 62, 64, 66 may be used to sense electricalactivity and may be used in combination with any of electrodes 40, 42,44, 45, 46, 47, 48, 50, 58. In at least one embodiment, the RV elongatedelectrode 62 may be used to sense electrical activity of a patient'sheart during the delivery of pacing therapy (e.g., in combination withthe housing electrode 58, or defibrillation electrode-to-housingelectrode vector).

The configuration of the exemplary therapy system 10 illustrated inFIGS. 9-11 is merely one example. In other examples, the therapy systemmay include epicardial leads and/or patch electrodes instead of or inaddition to the transvenous leads 18, 20, 22 illustrated in FIG. 9.Additionally, in other examples, the therapy system 10 may be implantedin/around the cardiac space without transvenous leads (e.g.,leadless/wireless pacing systems) or with leads implanted (e.g.,implanted transvenously or using approaches) into the left chambers ofthe heart (in addition to or replacing the transvenous leads placed intothe right chambers of the heart as illustrated in FIG. 9). Further, inone or more embodiments, the IMD 16 need not be implanted within thepatient 14. For example, the IMD 16 may deliver various cardiactherapies to the heart 12 via percutaneous leads that extend through theskin of the patient 14 to a variety of positions within or outside ofthe heart 12. In one or more embodiments, the system 10 may utilizewireless pacing (e.g., using energy transmission to the intracardiacpacing component(s) via ultrasound, inductive coupling, RF, etc.) andsensing cardiac activation using electrodes on the can/housing and/or onsubcutaneous leads.

In other examples of therapy systems that provide electrical stimulationtherapy to the heart 12, such therapy systems may include any suitablenumber of leads coupled to the IMD 16, and each of the leads may extendto any location within or proximate to the heart 12. For example, otherexamples of therapy systems may include three transvenous leads locatedas illustrated in FIGS. 9-11. Still further, other therapy systems mayinclude a single lead that extends from the IMD 16 into the right atrium26 or the right ventricle 28, or two leads that extend into a respectiveone of the right atrium 26 and the right ventricle 28.

FIG. 11A is a functional block diagram of one exemplary configuration ofthe IMD 16. As shown, the IMD 16 may include a control module 81, atherapy delivery module 84 (e.g., which may include a stimulationgenerator), a sensing module 86, and a power source 90.

The control module 81 may include a processor 80, memory 82, and atelemetry module 88. The memory 82 may include computer-readableinstructions that, when executed, e.g., by the processor 80, cause theIMD 16 and/or the control module 81 to perform various functionsattributed to the IMD 16 and/or the control module 81 described herein.Further, the memory 82 may include any volatile, non-volatile, magnetic,optical, and/or electrical media, such as a random-access memory (RAM),read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasableprogrammable ROM (EEPROM), flash memory, and/or any other digital media.An exemplary capture management module may be the left ventricularcapture management (LVCM) module described in U.S. Pat. No. 7,684,863entitled “LV THRESHOLD MEASUREMENT AND CAPTURE MANAGEMENT” and issuedMar. 23, 2010, which is incorporated herein by reference in itsentirety.

The processor 80 of the control module 81 may include any one or more ofa microprocessor, a controller, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field-programmablegate array (FPGA), and/or equivalent discrete or integrated logiccircuitry. In some examples, the processor 80 may include multiplecomponents, such as any combination of one or more microprocessors, oneor more controllers, one or more DSPs, one or more ASICs, and/or one ormore FPGAs, as well as other discrete or integrated logic circuitry. Thefunctions attributed to the processor 80 herein may be embodied assoftware, firmware, hardware, or any combination thereof.

The control module 81 may control the therapy delivery module 84 todeliver therapy (e.g., electrical stimulation therapy such as pacing) tothe heart 12 according to a selected one or more therapy programs, whichmay be stored in the memory 82. More, specifically, the control module81 (e.g., the processor 80) may control various parameters of theelectrical stimulus delivered by the therapy delivery module 84 such as,e.g., AV delays, VV delays, pacing pulses with the amplitudes, pulsewidths, frequency, or electrode polarities, etc., which may be specifiedby one or more selected therapy programs (e.g., AV and/or VV delayadjustment programs, pacing therapy programs, pacing recovery programs,capture management programs, etc.). As shown, the therapy deliverymodule 84 is electrically coupled to electrodes 40, 42, 44, 45, 46, 47,48, 50, 58, 62, 64, 66, e.g., via conductors of the respective lead 18,20, 22, or, in the case of housing electrode 58, via an electricalconductor disposed within housing 60 of IMD 16. Therapy delivery module84 may be configured to generate and deliver electrical stimulationtherapy such as pacing therapy to the heart 12 using one or more of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66.

For example, therapy delivery module 84 may deliver pacing stimulus(e.g., pacing pulses) via ring electrodes 40, 44, 45, 46, 47, 48 coupledto leads 18, 20, 22 and/or helical tip electrodes 42, 50 of leads 18,22. Further, for example, therapy delivery module 84 may deliverdefibrillation shocks to heart 12 via at least two of electrodes 58, 62,64, 66. In some examples, therapy delivery module 84 may be configuredto deliver pacing, cardioversion, or defibrillation stimulation in theform of electrical pulses. In other examples, therapy delivery module 84may be configured deliver one or more of these types of stimulation inthe form of other signals, such as sine waves, square waves, and/orother substantially continuous time signals.

The IMD 16 may further include a switch module 85 and the control module81 (e.g., the processor 80) may use the switch module 85 to select,e.g., via a data/address bus, which of the available electrodes are usedto deliver therapy such as pacing pulses for pacing therapy, or which ofthe available electrodes are used for sensing. The switch module 85 mayinclude a switch array, switch matrix, multiplexer, or any other type ofswitching device suitable to selectively couple the sensing module 86and/or the therapy delivery module 84 to one or more selectedelectrodes. More specifically, the therapy delivery module 84 mayinclude a plurality of pacing output circuits. Each pacing outputcircuit of the plurality of pacing output circuits may be selectivelycoupled, e.g., using the switch module 85, to one or more of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 (e.g., a pairof electrodes for delivery of therapy to a bipolar or multipolar pacingvector). In other words, each electrode can be selectively coupled toone of the pacing output circuits of the therapy delivery module usingthe switching module 85.

The sensing module 86 is coupled (e.g., electrically coupled) to sensingapparatus, which may include, among additional sensing apparatus, theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 to monitorelectrical activity of the heart 12, e.g., electrocardiogram(ECG)/electrogram (EGM) signals, etc. The ECG/EGM signals may be used tomeasure or monitor activation times (e.g., ventricular activationstimes, etc.), heart rate (HR), heart rate variability (HRV), heart rateturbulence (HRT), deceleration/acceleration capacity, decelerationsequence incidence, T-wave alternans (TWA), P-wave to P-wave intervals(also referred to as the P-P intervals or A-A intervals), R-wave toR-wave intervals (also referred to as the R-R intervals or V-Vintervals), P-wave to QRS complex intervals (also referred to as the P-Rintervals, A-V intervals, or P-Q intervals), QRS-complex morphology, STsegment (i.e., the segment that connects the QRS complex and theT-wave), T-wave changes, QT intervals, electrical vectors, etc.

The switch module 85 may also be used with the sensing module 86 toselect which of the available electrodes are used, or enabled, to, e.g.,sense electrical activity of the patient's heart (e.g., one or moreelectrical vectors of the patient's heart using any combination of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66). Likewise,the switch module 85 may also be used with the sensing module 86 toselect which of the available electrodes are not to be used (e.g.,disabled) to, e.g., sense electrical activity of the patient's heart(e.g., one or more electrical vectors of the patient's heart using anycombination of the electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62,64, 66), etc. In some examples, the control module 81 may select theelectrodes that function as sensing electrodes via the switch modulewithin the sensing module 86, e.g., by providing signals via adata/address bus.

In some examples, sensing module 86 includes a channel that includes anamplifier with a relatively wider pass band than the R-wave or P-waveamplifiers. Signals from the selected sensing electrodes may be providedto a multiplexer, and thereafter converted to multi-bit digital signalsby an analog-to-digital converter for storage in memory 82, e.g., as anelectrogram (EGM). In some examples, the storage of such EGMs in memory82 may be under the control of a direct memory access circuit.

In some examples, the control module 81 may operate as an interruptdriven device, and may be responsive to interrupts from pacer timing andcontrol module, where the interrupts may correspond to the occurrencesof sensed P-waves and R-waves and the generation of cardiac pacingpulses. Any necessary mathematical calculations may be performed by theprocessor 80 and any updating of the values or intervals controlled bythe pacer timing and control module may take place following suchinterrupts. A portion of memory 82 may be configured as a plurality ofrecirculating buffers, capable of holding one or more series of measuredintervals, which may be analyzed by, e.g., the processor 80 in responseto the occurrence of a pace or sense interrupt to determine whether thepatient's heart 12 is presently exhibiting atrial or ventriculartachyarrhythmia.

The telemetry module 88 of the control module 81 may include anysuitable hardware, firmware, software, or any combination thereof forcommunicating with another device, such as a programmer. For example,under the control of the processor 80, the telemetry module 88 mayreceive downlink telemetry from and send uplink telemetry to aprogrammer with the aid of an antenna, which may be internal and/orexternal. The processor 80 may provide the data to be uplinked to aprogrammer and the control signals for the telemetry circuit within thetelemetry module 88, e.g., via an address/data bus. In some examples,the telemetry module 88 may provide received data to the processor 80via a multiplexer.

The various components of the IMD 16 are further coupled to a powersource 90, which may include a rechargeable or non-rechargeable battery.A non-rechargeable battery may be selected to last for several years,while a rechargeable battery may be inductively charged from an externaldevice, e.g., on a daily or weekly basis.

FIG. 11B is another embodiment of a functional block diagram for IMD 16that depicts bipolar RA lead 22, bipolar RV lead 18, and bipolar LV CSlead 20 without the LA CS pace/sense electrodes and coupled with animplantable pulse generator (IPG) circuit 31 having programmable modesand parameters of a bi-ventricular DDD/R type known in the pacing art.In turn, the sensor signal processing circuit 91 indirectly couples tothe timing circuit 43 and via data and control bus to microcomputercircuitry 33. The IPG circuit 31 is illustrated in a functional blockdiagram divided generally into a microcomputer circuit 33 and a pacingcircuit 21. The pacing circuit 21 includes the digital controller/timercircuit 43, the output amplifiers circuit 51, the sense amplifierscircuit 55, the RF telemetry transceiver 41, the activity sensor circuit35 as well as a number of other circuits and components described below.

Crystal oscillator circuit 89 provides the basic timing clock for thepacing circuit 21 while battery 29 provides power. Power-on-resetcircuit 87 responds to initial connection of the circuit to the batteryfor defining an initial operating condition and similarly, resets theoperative state of the device in response to detection of a low batterycondition. Reference mode circuit 37 generates stable voltage referenceand currents for the analog circuits within the pacing circuit 21.Analog-to-digital converter (ADC) and multiplexer circuit 39 digitizeanalog signals and voltage to provide, e.g., real time telemetry ofcardiac signals from sense amplifiers 55 for uplink transmission via RFtransmitter and receiver circuit 41. Voltage reference and bias circuit37, ADC and multiplexer 39, power-on-reset circuit 87, and crystaloscillator circuit 89 may correspond to any of those used in exemplaryimplantable cardiac pacemakers.

If the IPG is programmed to a rate responsive mode, the signals outputby one or more physiologic sensors are employed as a rate controlparameter (RCP) to derive a physiologic escape interval. For example,the escape interval is adjusted proportionally to the patient's activitylevel developed in the patient activity sensor (PAS) circuit 35 in thedepicted, exemplary IPG circuit 31. The patient activity sensor 27 iscoupled to the IPG housing and may take the form of a piezoelectriccrystal transducer. The output signal of the patient activity sensor 27may be processed and used as a RCP. Sensor 27 generates electricalsignals in response to sensed physical activity that are processed byactivity circuit 35 and provided to digital controller/timer circuit 43.Activity circuit 35 and associated sensor 27 may correspond to thecircuitry disclosed in U.S. Pat. No. 5,052,388 entitled “METHOD ANDAPPARATUS FOR IMPLEMENTING ACTIVITY SENSING IN A PULSE GENERATOR” andissued on Oct. 1, 1991 and U.S. Pat. No. 4,428,378 entitled “RATEADAPTIVE PACER” and issued on Jan. 31, 1984, each of which isincorporated herein by reference in its entirety. Similarly, theexemplary systems, apparatus, and methods described herein may bepracticed in conjunction with alternate types of sensors such asoxygenation sensors, pressure sensors, pH sensors, and respirationsensors, for use in providing rate responsive pacing capabilities.Alternately, QT time may be used as a rate indicating parameter, inwhich case no extra sensor is required. Similarly, the exemplaryembodiments described herein may also be practiced in non-rateresponsive pacemakers.

Data transmission to and from the external programmer is accomplished byway of the telemetry antenna 57 and an associated RF transceiver 41,which serves both to demodulate received downlink telemetry and totransmit uplink telemetry. Uplink telemetry capabilities may include theability to transmit stored digital information, e.g., operating modesand parameters, EGM histograms, and other events, as well as real timeEGMs of atrial and/or ventricular electrical activity and marker channelpulses indicating the occurrence of sensed and paced depolarizations inthe atrium and ventricle.

Microcomputer 33 contains a microprocessor 80 and associated systemclock and on-processor RAM and ROM chips 82A and 82B, respectively. Inaddition, microcomputer circuit 33 includes a separate RAM/ROM chip 82Cto provide additional memory capacity. Microprocessor 80 normallyoperates in a reduced power consumption mode and is interrupt driven.Microprocessor 80 is awakened in response to defined interrupt events,which may include A-TRIG, RV-TRIG, LV-TRIG signals generated by timersin digital timer/controller circuit 43 and A-EVENT, RV-EVENT, andLV-EVENT signals generated by sense amplifiers circuit 55, among others.The specific values of the intervals and delays timed out by digitalcontroller/timer circuit 43 are controlled by the microcomputer circuit33 by way of data and control bus from programmed-in parameter valuesand operating modes. In addition, if programmed to operate as a rateresponsive pacemaker, a timed interrupt, e.g., every cycle or every twoseconds, may be provided in order to allow the microprocessor to analyzethe activity sensor data and update the basic A-A, V-A, or V-V escapeinterval, as applicable. In addition, the microprocessor 80 may alsoserve to define variable, operative AV delay intervals, V-V delayintervals, and the energy delivered to each ventricle and/or atrium.

In one embodiment, microprocessor 80 is a custom microprocessor adaptedto fetch and execute instructions stored in RAM/ROM unit 82 in aconventional manner. It is contemplated, however, that otherimplementations may be suitable to practice the present invention. Forexample, an off-the-shelf, commercially available microprocessor ormicrocontroller, or custom application-specific, hardwired logic, orstate-machine type circuit may perform the functions of microprocessor80.

Digital controller/timer circuit 43 operates under the general controlof the microcomputer 33 to control timing and other functions within thepacing circuit 21 and includes a set of timing and associated logiccircuits of which certain ones pertinent to the present invention aredepicted. The depicted timing circuits include URI/LRI timers 83A, V-Vdelay timer 83B, intrinsic interval timers 83C for timing elapsedV-EVENT to V-EVENT intervals or V-EVENT to A-EVENT intervals or the V-Vconduction interval, escape interval timers 83D for timing A-A, V-A,and/or V-V pacing escape intervals, an AV delay interval timer 83E fortiming the A-LVp delay (or A-RVp delay) from a preceding A-EVENT orA-TRIG, a post-ventricular timer 83F for timing post-ventricular timeperiods, and a date/time clock 83G.

The AV delay interval timer 83E is loaded with an appropriate delayinterval for one ventricular chamber (e.g., either an A-RVp delay or anA-LVp) to time-out starting from a preceding A-PACE or A-EVENT. Theinterval timer 83E triggers pacing stimulus delivery, and can be basedon one or more prior cardiac cycles (or from a data set empiricallyderived for a given patient).

The post-event timer 83F times out the post-ventricular time periodfollowing an RV-EVENT or LV-EVENT or a RV-TRIG or LV-TRIG andpost-atrial time periods following an A-EVENT or A-TRIG. The durationsof the post-event time periods may also be selected as programmableparameters stored in the microcomputer 33. The post-ventricular timeperiods include the PVARP, a post-atrial ventricular blanking period(PAVBP), a ventricular blanking period (VBP), a post-ventricular atrialblanking period (PVARP) and a ventricular refractory period (VRP)although other periods can be suitably defined depending, at least inpart, on the operative circuitry employed in the pacing engine. Thepost-atrial time periods include an atrial refractory period (ARP)during which an A-EVENT is ignored for the purpose of resetting any AVdelay, and an atrial blanking period (ABP) during which atrial sensingis disabled. It should be noted that the starting of the post-atrialtime periods and the AV delays can be commenced substantiallysimultaneously with the start or end of each A-EVENT or A-TRIG or, inthe latter case, upon the end of the A-PACE which may follow the A-TRIG.Similarly, the starting of the post-ventricular time periods and the V-Aescape interval can be commenced substantially simultaneously with thestart or end of the V-EVENT or V-TRIG or, in the latter case, upon theend of the V-PACE which may follow the V-TRIG. The microprocessor 80also optionally calculates AV delays, VV delays, post-ventricular timeperiods, and post-atrial time periods that vary with the sensor basedescape interval established in response to the RCP(s) and/or with theintrinsic atrial and/or ventricular rate.

The output amplifiers circuit 51 contains a RA pace pulse generator (anda LA pace pulse generator if LA pacing is provided), a RV pace pulsegenerator, a LV pace pulse generator, and/or any other pulse generatorconfigured to provide atrial and ventricular pacing. In order to triggergeneration of an RV-PACE or LV-PACE pulse, digital controller/timercircuit 43 generates the RV-TRIG signal at the time-out of the A-RVpdelay (in the case of RV pre-excitation) or the LV-TRIG at the time-outof the A-LVp delay (in the case of LV pre-excitation) provided by AVdelay interval timer 83E (or the V-V delay timer 83B). Similarly,digital controller/timer circuit 43 generates an RA-TRIG signal thattriggers output of an RA-PACE pulse (or an LA-TRIG signal that triggersoutput of an LA-PACE pulse, if provided) at the end of the V-A escapeinterval timed by escape interval timers 83D.

The output amplifiers circuit 51 includes switching circuits forcoupling selected pace electrode pairs from among the lead conductorsand the IND-CAN electrode 20 to the RA pace pulse generator (and LA pacepulse generator if provided), RV pace pulse generator and LV pace pulsegenerator. Pace/sense electrode pair selection and control circuit 53selects lead conductors and associated pace electrode pairs to becoupled with the atrial and ventricular output amplifiers within outputamplifiers circuit 51 for accomplishing RA, LA, RV and LV pacing.

The sense amplifiers circuit 55 contains sense amplifiers for atrial andventricular pacing and sensing. High impedance P-wave and R-wave senseamplifiers may be used to amplify a voltage difference signal that isgenerated across the sense electrode pairs by the passage of cardiacdepolarization wavefronts. The high impedance sense amplifiers use highgain to amplify the low amplitude signals and rely on pass band filters,time domain filtering and amplitude threshold comparison to discriminatea P-wave or R-wave from background electrical noise. Digitalcontroller/timer circuit 43 controls sensitivity settings of the atrialand ventricular sense amplifiers 55.

The sense amplifiers may be uncoupled from the sense electrodes duringthe blanking periods before, during, and after delivery of a pace pulseto any of the pace electrodes of the pacing system to avoid saturationof the sense amplifiers. The sense amplifiers circuit 55 includesblanking circuits for uncoupling the selected pairs of the leadconductors and the IND-CAN electrode 20 from the inputs of the RA senseamplifier (and LA sense amplifier if provided), RV sense amplifier andLV sense amplifier during the ABP, PVABP and VBP. The sense amplifierscircuit 55 also includes switching circuits for coupling selected senseelectrode lead conductors and the IND-CAN electrode 20 to the RA senseamplifier (and LA sense amplifier if provided), RV sense amplifier andLV sense amplifier. Again, sense electrode selection and control circuit53 selects conductors and associated sense electrode pairs to be coupledwith the atrial and ventricular sense amplifiers within the outputamplifiers circuit 51 and sense amplifiers circuit 55 for accomplishingRA, LA, RV, and LV sensing along desired unipolar and bipolar sensingvectors.

Right atrial depolarizations or P-waves in the RA-SENSE signal that aresensed by the RA sense amplifier result in a RA-EVENT signal that iscommunicated to the digital controller/timer circuit 43. Similarly, leftatrial depolarizations or P-waves in the LA-SENSE signal that are sensedby the LA sense amplifier, if provided, result in a LA-EVENT signal thatis communicated to the digital controller/timer circuit 43. Ventriculardepolarizations or R-waves in the RV-SENSE signal are sensed by aventricular sense amplifier result in an RV-EVENT signal that iscommunicated to the digital controller/timer circuit 43. Similarly,ventricular depolarizations or R-waves in the LV-SENSE signal are sensedby a ventricular sense amplifier result in an LV-EVENT signal that iscommunicated to the digital controller/timer circuit 43. The RV-EVENT,LV-EVENT, and RA-EVENT, LA-SENSE signals may be refractory ornon-refractory, and can inadvertently be triggered by electrical noisesignals or aberrantly conducted depolarization waves rather than trueR-waves or P-waves.

The techniques described in this disclosure, including those attributedto the IMD 16, the computing apparatus 140, and/or various constituentcomponents, may be implemented, at least in part, in hardware, software,firmware, or any combination thereof. For example, various aspects ofthe techniques may be implemented within one or more processors,including one or more microprocessors, DSPs, ASICs, FPGAs, or any otherequivalent integrated or discrete logic circuitry, as well as anycombinations of such components, embodied in programmers, such asphysician or patient programmers, stimulators, image processing devices,or other devices. The term “module,” “processor,” or “processingcircuitry” may generally refer to any of the foregoing logic circuitry,alone or in combination with other logic circuitry, or any otherequivalent circuitry.

Such hardware, software, and/or firmware may be implemented within thesame device or within separate devices to support the various operationsand functions described in this disclosure. In addition, any of thedescribed units, modules, or components may be implemented together orseparately as discrete but interoperable logic devices. Depiction ofdifferent features as modules or units is intended to highlightdifferent functional aspects and does not necessarily imply that suchmodules or units must be realized by separate hardware or softwarecomponents. Rather, functionality associated with one or more modules orunits may be performed by separate hardware or software components, orintegrated within common or separate hardware or software components.

When implemented in software, the functionality ascribed to the systems,devices and techniques described in this disclosure may be embodied asinstructions on a computer-readable medium such as RAM, ROM, NVRAM,EEPROM, FLASH memory, magnetic data storage media, optical data storagemedia, or the like. The instructions may be executed by processingcircuitry and/or one or more processors to support one or more aspectsof the functionality described in this disclosure.

ILLUSTRATIVE EMBODIMENTS Embodiment 1

A system for use in cardiac evaluation comprising:

electrode apparatus comprising a plurality of external electrodes to belocated proximate a patient's skin;

display comprising a graphical user interface to present information foruse in assisting a user in at least one of assessing a patient's cardiachealth, evaluating and adjusting cardiac therapy delivered to a patient,and navigating at least one implantable electrode to a region of thepatient's heart; and computing apparatus comprising processingcircuitry, the computing apparatus operably coupled to the electrodeapparatus and the display, the computing apparatus configured to:

monitor electrical activity from the patient's skin using the pluralityof external electrodes,

display, on the graphical user interface, a graphical map comprises aplurality of electrode graphical elements corresponding to andpositioned on the graphical map in relation to the physical location ofthe plurality of electrodes located proximate the patient's skin,wherein the graphical map extends from a left portion corresponding toanterior side of the patient to a middle portion corresponding to theleft side of the patient to a right side corresponding to the posteriorside of the patient, and

display, on the graphical user interface, an effectiveness valueproximate each of the plurality of electrode graphical elementsrepresentative of the effectiveness of the corresponding electrode inproviding a valid sensing signal from the tissue of the patient.

Embodiment 2

A method comprising:

providing a plurality of external electrodes to be located proximate apatient's skin;

monitoring electrical activity from the patient's skin using theplurality of external electrodes;

displaying, on the graphical user interface, a graphical map comprisinga plurality of electrode graphical elements corresponding to andpositioned on the graphical map in relation to the physical location ofthe plurality of electrodes located proximate the patient's skin,wherein the graphical map extends from a left portion corresponding toanterior side of the patient to a middle portion corresponding to theleft side of the patient to a right side corresponding to the posteriorside of the patient; and

displaying, on the graphical user interface, an effectiveness valueproximate each of the plurality of electrode graphical elementsrepresentative of the effectiveness of the corresponding electrode inproviding a valid sensing signal from the tissue of the patient.

Embodiment 3

The embodiment as set forth in any one of embodiments 1-2, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises displaying, on the graphical user interface, aprincipal electrodes graphical region proximate one or more electrodegraphical elements to indicate which of the plurality of electrodes mostsignificant.

Embodiment 4

The embodiment as set forth in any one of embodiments 1-3, wherein theeffectiveness value comprises one of the following three values: goodsignal (or good contact), poor signal, and not in contact.

Embodiment 5

The embodiment as set forth in any one of embodiments 1-4, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises displaying, on the graphical user interface, a globalelectrode connection status message indicative of the state of theplurality of electrodes providing valid sensing signals from the tissueof the patient.

Embodiment 6

A system for use in cardiac evaluation comprising:

electrode apparatus comprising a plurality of external electrodes to belocated proximate a patient's skin;

display comprising a graphical user interface to present information foruse in assisting a user in at least one of assessing a patient's cardiachealth, evaluating and adjusting cardiac therapy delivered to a patient,and navigating at least one implantable electrode to a region of thepatient's heart; and

computing apparatus comprising processing circuitry, the computingapparatus operably coupled to the electrode apparatus and the display,the computing apparatus configured to:

monitor electrical activity from the patient's skin using the pluralityof external electrodes resulting in a plurality of electrode signals,display, on the graphical user interface, the plurality of electrodesignals over a plurality of cardiac cycles,

select or allow a user to select one cardiac cycle of the plurality ofcardiac cycles, and

display, on the graphical user interface, a graphical map of electricalactivation based on the monitored electrical activity for the selectedcardiac cycle.

Embodiment 7

A method comprising:

providing a plurality of external electrodes to be located proximate apatient's skin;

monitoring electrical activity from the patient's skin using theplurality of external electrodes resulting in a plurality of electrodesignals;

displaying, on the graphical user interface, the plurality of electrodesignals over a plurality of cardiac cycles;

selecting or allowing a user to select one cardiac cycle of theplurality of cardiac cycles; and

displaying, on the graphical user interface, a graphical map ofelectrical activation based on the monitored electrical activity for theselected cardiac cycle.

Embodiment 8

The embodiment as set forth in any one of embodiments 6-7, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises displaying, on the graphical user interface, aplurality of electrode elements corresponding to and positioned on thegraphical map of electrical activation in relation to the physicallocation of the plurality of electrodes located proximate the patient'sskin, wherein the graphical map extends from a left portioncorresponding to anterior side of the patient to a middle portioncorresponding to the left side of the patient to a right sidecorresponding to the posterior side of the patient.

Embodiment 9

The embodiment as set forth embodiment 8, wherein the computingapparatus is further configured to execute or the method furthercomprises allowing a user to hide or display the plurality of electrodeelements.

Embodiment 10

The embodiment as set forth in any one of embodiments 8-9, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises graphically indicating, on graphical map of electricalactivation, one or more areas of conduction block based on the monitoredelectrical activity for the selected cardiac cycle.

Embodiment 11

The embodiment as set forth in any one of embodiments 8-10, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises graphically indicating, on the graphical userinterface, which of the plurality of electrode elements corresponds toelectrodes that are ineffective in providing a valid sensing signal fromthe tissue of the patient.

Embodiment 12

The embodiment as set forth in any one of embodiments 6-11, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises interpolating the electrical activation of each areaof the graphical map of electrical activation corresponding correspondsto external electrodes that are ineffective in providing a valid sensingsignal from the tissue of the patient.

Embodiment 13

The embodiment as set forth in any one of embodiments 6-12, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises displaying at least one metric of electricalheterogeneity based on the monitored electrical activity for theselected cardiac cycle.

Embodiment 14

The embodiment as set forth in any one of embodiments 6-13, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises:

allowing a user to select a cardiac therapy scenario of a plurality ofdifferent cardiac therapy scenarios; and

displaying, on the graphical user interface, the plurality of electrodesignals over a plurality of cardiac cycles corresponding to the selectedcardiac therapy scenario.

Embodiment 15

The embodiment of embodiment 14, wherein each of the plurality ofdifferent cardiac therapy scenarios comprise at least one differentpacing configuration, AV delay, and LV pacing site.

Embodiment 16

The embodiment as set forth in any one of embodiments 6-15, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises selecting one cardiac cycle of the plurality ofcardiac cycles comprises selecting the cardiac cycle of the plurality ofcardiac based on at least one metric for each cardiac cycle based on asingle-cycle submetric and a cycle-series submetric, wherein thesingle-cycle submetric is based on at least two of the plurality ofelectrical signals during the cardiac cycle and the cycle-seriessubmetric is based on at least two of the plurality of electricalsignals during at least two cardiac cycles.

Embodiment 17

The embodiment as set forth in any one of embodiments 6-16, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises allowing a user to select an electrode set of aplurality of different electrode sets of the plurality of externalelectrodes, wherein the displayed plurality of electrode signals overthe plurality of cardiac cycles comprises only electrode signals of theselected electrode set, and the displayed graphical map of electricalactivation is based on the monitored electrical activity from onlyelectrode signals of the selected electrode set.

Embodiment 18

A system for use in cardiac evaluation comprising:

electrode apparatus comprising a plurality of external electrodes to belocated proximate a patient's skin;

display comprising a graphical user interface to present information foruse in assisting a user in at least one of assessing a patient's cardiachealth, evaluating and adjusting cardiac therapy delivered to a patient,and navigating at least one implantable electrode to a region of thepatient's heart; and

computing apparatus comprising processing circuitry, the computingapparatus operably coupled to the electrode apparatus and the display,the computing apparatus configured to:

monitor electrical activity from the patient's skin using the pluralityof external electrodes for each of a plurality of different cardiactherapy scenarios,

generate electrical heterogeneity information for each of the pluralityof different cardiac therapy scenarios based on the monitored electricalactivity,

display, on the graphical user interface, a cardiac therapy scenarioselection region to allow a user to select one or more of the pluralityof different cardiac therapy scenarios, and

displaying a ranking of the selected cardiac therapy scenarios based onthe generated electrical heterogeneity information.

Embodiment 19

A method comprising:

providing a plurality of external electrodes to be located proximate apatient's skin;

monitoring electrical activity from the patient's skin using theplurality of external electrodes for each of a plurality of differentcardiac therapy scenarios;

generating electrical heterogeneity information for each of theplurality of different cardiac therapy scenarios based on the monitoredelectrical activity;

displaying, on a graphical user interface, a cardiac therapy scenarioselection region to allow a user to select one or more of the pluralityof different cardiac therapy scenarios; and

displaying a ranking of the selected cardiac therapy scenarios based onthe generated electrical heterogeneity information.

Embodiment 20

The embodiment as set forth in any one of embodiments 18-19, wherein theelectrical heterogeneity information comprises a global standarddeviation of surrogate electrical activation times monitored by theplurality of external electrodes.

Embodiment 21

The embodiment as set forth in any one of embodiments 18-20, wherein theplurality of electrodes comprises two or more left external electrodesconfigured to be located proximate the left side of the patient, whereinthe electrical heterogeneity information comprises an average ofelectrical activation times monitored by the two or more left externalelectrodes.

Embodiment 22

The embodiment as set forth in any one of embodiments 18-21, wherein theselected cardiac therapy scenarios are ranked based on a primary metricof electrical heterogeneity.

Embodiment 23

The embodiment as set forth in embodiment 22, wherein two or more of theselected cardiac therapy scenarios are further ranked based on asecondary metric of electrical heterogeneity if the primary metric ofelectrical heterogeneity of the two more selected cardiac therapyscenarios are within a selected threshold from each other.

Embodiment 24

The embodiment as set forth in any one of embodiments 18-24, whereindisplaying a ranking of the selected cardiac therapy scenarios based onthe generated cardiac heterogeneity information comprises displaying aplurality of rankings of the different groups of selected cardiactherapy scenarios.

Embodiment 25

A system for use in cardiac evaluation comprising:

electrode apparatus comprising a plurality of external electrodes to belocated proximate a patient's skin;

display comprising a graphical user interface to present information foruse in assisting a user in at least one of assessing a patient's cardiachealth, evaluating and adjusting cardiac therapy delivered to a patient,and navigating at least one implantable electrode to a region of thepatient's heart; and

computing apparatus comprising processing circuitry, the computingapparatus operably coupled to the electrode apparatus and the display,the computing apparatus configured to:

monitor electrical activity from the patient's skin using the pluralityof external electrodes for each of a plurality of different cardiactherapy scenarios, and

display, on the graphical user interface, a plurality of graphical mapsof electrical activation based on the monitored electrical activity,each of the plurality of graphical maps of electrical activationcorresponding to a different cardiac therapy scenario of the pluralityof different cardiac therapy scenarios than each other.

Embodiment 26

A method comprising:

providing a plurality of external electrodes to be located proximate apatient's skin;

monitoring electrical activity from the patient's skin using theplurality of external electrodes for each of a plurality of differentcardiac therapy scenarios, and

displaying, on a graphical user interface, a plurality of graphical mapsof electrical activation based on the monitored electrical activity,each of the plurality of graphical maps of electrical activationcorresponding to a different cardiac therapy scenario of the pluralityof different cardiac therapy scenarios than each other.

Embodiment 27

The embodiment as set forth in any one of embodiments 25-26, whereineach of the plurality of different cardiac therapy scenarios comprise atleast one different pacing configuration, AV delay, and LV pacing site.

Embodiment 28

The embodiment as set forth in any one of embodiments 25-27, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises:

generating electrical heterogeneity information for each of theplurality of different cardiac therapy scenarios based on the monitoredelectrical activity; and

displaying the electrical heterogeneity information proximate to each ofthe plurality of graphical maps of electrical activation correspondingto the same cardiac therapy scenario as the graphical map of electricalactivation.

Embodiment 29

The embodiment as set forth in embodiment 28, wherein the plurality ofelectrodes comprises two or more left external electrodes configured tobe located proximate the left side of the patient, wherein theelectrical heterogeneity information comprises at least one of:

a global standard deviation of surrogate electrical activation timesmonitored by the plurality of external electrodes; and

a left metric of electrical activation times monitored by the two ormore left external electrodes.

Embodiment 30

The embodiment as set forth in any one of embodiments 28-29, wherein theelectrical heterogeneity information comprises a percentage change inthe electrical heterogeneity information determined from electricalactivity monitored during the corresponding cardiac therapy scenario andelectrical heterogeneity information determined from electrical activitymonitored during intrinsic cardiac activation.

Embodiment 31

The embodiment as set forth in any one of embodiments 25-30, wherein thecomputing apparatus is further configured to execute or the methodfurther comprises displaying, on the graphical user interface, agraphical map of intrinsic electrical activation based on electricalactivity monitored during intrinsic cardiac activation.

This disclosure has been provided with reference to illustrativeembodiments and is not meant to be construed in a limiting sense. Asdescribed previously, one skilled in the art will recognize that othervarious illustrative applications may use the techniques as describedherein to take advantage of the beneficial characteristics of theapparatus and methods described herein. Various modifications of theillustrative embodiments, as well as additional embodiments of thedisclosure, will be apparent upon reference to this description.

What is claimed:
 1. A system for use in cardiac evaluation comprising:electrode apparatus comprising a plurality of external electrodes to belocated proximate a patient's skin; display comprising a graphical userinterface to present information for use in assisting a user in at leastone of assessing a patient's cardiac health, evaluating and adjustingcardiac therapy delivered to a patient, and navigating at least oneimplantable electrode to a region of the patient's heart; and computingapparatus comprising processing circuitry, the computing apparatusoperably coupled to the electrode apparatus and the display, thecomputing apparatus configured to: monitor electrical activity from thepatient's skin using the plurality of external electrodes for each of aplurality of different cardiac therapy scenarios, generate electricalheterogeneity information for each of the plurality of different cardiactherapy scenarios based on the monitored electrical activity, display,on the graphical user interface, a cardiac therapy scenario selectionregion to allow a user to select one or more of the plurality ofdifferent cardiac therapy scenarios, and displaying a ranking of theselected cardiac therapy scenarios based on the generated electricalheterogeneity information.
 2. The system of claim 1, wherein theelectrical heterogeneity information comprises a global standarddeviation of surrogate electrical activation times monitored by theplurality of external electrodes.
 3. The system of claim 1, wherein theplurality of electrodes comprises two or more left external electrodesconfigured to be located proximate the left side of the patient, whereinthe electrical heterogeneity information comprises an average ofelectrical activation times monitored by the two or more left externalelectrodes.
 4. The system of claim 1, wherein the selected cardiactherapy scenarios are ranked based on a primary metric of electricalheterogeneity.
 5. The system of claim 4, wherein two or more of theselected cardiac therapy scenarios are further ranked based on asecondary metric of electrical heterogeneity if the primary metric ofelectrical heterogeneity of the two more selected cardiac therapyscenarios are within a selected threshold from each other.
 6. The systemof claim 1, wherein displaying a ranking of the selected cardiac therapyscenarios based on the generated cardiac heterogeneity informationcomprises displaying a plurality of rankings of the different groups ofselected cardiac therapy scenarios.
 7. A method comprising: providing aplurality of external electrodes to be located proximate a patient'sskin; monitoring electrical activity from the patient's skin using theplurality of external electrodes for each of a plurality of differentcardiac therapy scenarios; generating electrical heterogeneityinformation for each of the plurality of different cardiac therapyscenarios based on the monitored electrical activity; displaying, on agraphical user interface, a cardiac therapy scenario selection region toallow a user to select one or more of the plurality of different cardiactherapy scenarios; and displaying a ranking of the selected cardiactherapy scenarios based on the generated electrical heterogeneityinformation.
 8. The method of claim 7, wherein the electricalheterogeneity information comprises a global standard deviation ofsurrogate electrical activation times monitored by the plurality ofexternal electrodes.
 9. The method of claim 7, wherein the plurality ofelectrodes comprises two or more left external electrodes configured tobe located proximate the left side of the patient, wherein theelectrical heterogeneity information comprises an average of electricalactivation times monitored by the two or more left external electrodes.10. The method of claim 7, wherein the selected cardiac therapyscenarios are ranked based on a primary metric of electricalheterogeneity.
 11. The method of claim 10, wherein two or more of theselected cardiac therapy scenarios are further ranked based on asecondary metric of electrical heterogeneity if the primary metric ofelectrical heterogeneity of the two more selected cardiac therapyscenarios are within a selected threshold from each other.
 12. Themethod of claim 7, wherein displaying a ranking of the selected cardiactherapy scenarios based on the generated cardiac heterogeneityinformation comprises displaying a plurality of rankings of thedifferent groups of selected cardiac therapy scenarios.
 13. A system foruse in cardiac evaluation comprising: electrode apparatus comprising aplurality of external electrodes to be located proximate a patient'sskin; display comprising a graphical user interface to presentinformation for use in assisting a user in at least one of assessing apatient's cardiac health, evaluating and adjusting cardiac therapydelivered to a patient, and navigating at least one implantableelectrode to a region of the patient's heart; and computing apparatuscomprising processing circuitry, the computing apparatus operablycoupled to the electrode apparatus and the display, the computingapparatus configured to: monitor electrical activity from the patient'sskin using the plurality of external electrodes for each of a pluralityof different cardiac therapy scenarios, and display, on the graphicaluser interface, a plurality of graphical maps of electrical activationbased on the monitored electrical activity, each of the plurality ofgraphical maps of electrical activation corresponding to a differentcardiac therapy scenario of the plurality of different cardiac therapyscenarios than each other.
 14. The system of claim 13, wherein each ofthe plurality of different cardiac therapy scenarios comprise at leastone different pacing configuration, AV delay, and LV pacing site. 15.The system of claim 13, wherein the computing apparatus is furtherconfigured to: generate electrical heterogeneity information for each ofthe plurality of different cardiac therapy scenarios based on themonitored electrical activity; and display the electrical heterogeneityinformation proximate to each of the plurality of graphical maps ofelectrical activation corresponding to the same cardiac therapy scenarioas the graphical map of electrical activation.
 16. The system of claim15, wherein the plurality of electrodes comprises two or more leftexternal electrodes configured to be located proximate the left side ofthe patient, wherein the electrical heterogeneity information comprisesat least one of: a global standard deviation of surrogate electricalactivation times monitored by the plurality of external electrodes; anda left metric of electrical activation times monitored by the two ormore left external electrodes.
 17. The system of claim 16, wherein theelectrical heterogeneity information comprises a percentage change inthe electrical heterogeneity information determined from electricalactivity monitored during the corresponding cardiac therapy scenario andelectrical heterogeneity information determined from electrical activitymonitored during intrinsic cardiac activation.
 18. The system of claim13, wherein the computing apparatus is further configured to display, onthe graphical user interface, a graphical map of intrinsic electricalactivation based on electrical activity monitored during intrinsiccardiac activation.
 19. A method comprising: providing a plurality ofexternal electrodes to be located proximate a patient's skin; monitoringelectrical activity from the patient's skin using the plurality ofexternal electrodes for each of a plurality of different cardiac therapyscenarios, and displaying, on a graphical user interface, a plurality ofgraphical maps of electrical activation based on the monitoredelectrical activity, each of the plurality of graphical maps ofelectrical activation corresponding to a different cardiac therapyscenario of the plurality of different cardiac therapy scenarios thaneach other.
 20. The method of claim 19, wherein each of the plurality ofdifferent cardiac therapy scenarios comprise at least one differentpacing configuration, AV delay, and LV pacing site.
 21. The method ofclaim 19, the method further comprising: generating electricalheterogeneity information for each of the plurality of different cardiactherapy scenarios based on the monitored electrical activity; anddisplaying the electrical heterogeneity information proximate to each ofthe plurality of graphical maps of electrical activation correspondingto the same cardiac therapy scenario as the graphical map of electricalactivation.
 22. The method of claim 21, wherein the plurality ofelectrodes comprises two or more left external electrodes configured tobe located proximate the left side of the patient, wherein theelectrical heterogeneity information comprises at least one of: a globalstandard deviation of surrogate electrical activation times monitored bythe plurality of external electrodes; and a left metric of electricalactivation times monitored by the two or more left external electrodes.23. The method of claim 21, wherein the electrical heterogeneityinformation comprises a percentage change in the electricalheterogeneity information determined from electrical activity monitoredduring the corresponding cardiac therapy scenario and electricalheterogeneity information determined from electrical activity monitoredduring intrinsic cardiac activation.
 24. The method of claim 19, themethod further comprising displaying, on the graphical user interface, agraphical map of intrinsic electrical activation based on electricalactivity monitored during intrinsic cardiac activation.